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Essential Skills to Become a Data Scientist

The demand for Data Science professionals is now at an all-time high. There are companies in virtually every industry looking to extract the most value from the heaps of information generated on a daily basis.With the trend for Data Science catching up like never before, organizations are making complete use of their internal data assets to further examine the integration of hundreds of third-party data sources. What is crucial here is the role of the data scientists.Not very long back, the teams playing the key role of working on the data always found their places in the back rooms of multifold IT organizations. The teams though sitting on the backseat would help in steering the various corporate systems with the required data that acted as the fuel to keep the activities running. The critical database tasks performed by the teams responsible allowed corporate executives to report on operations activities and deliver financial results.When you take up a career in Data Science, your previous experience or skills do not matter. As a matter of fact, you would need a whole new range of skills to pursue a career in Data Science. Below are the skills required to become a top dog in Data Science.What should Data Scientists knowData scientists are expected to have knowledge and expertise in the following domains:The areas arch over dozens of languages, frameworks, and technologies that data scientists need to learn. Data scientists should always have the curiosity to amass more knowledge in their domain so that they stay relevant in this dynamic field.The world of Data Science demands certain important attributes and skills, according to IT leaders, industry analysts, data scientists, and others.How to become a Data Scientist?A majority of Data scientists already have a Master’s degree. If Master’s degree does not quench their thirst for more degrees, some even go on to acquire PhD degrees. Mind you, there are exceptions too. It isn’t mandatory that you should be an expert in a particular subject to become a Data Scientist. You could become one even with a qualification in Computer Science, Physical Sciences, Natural Sciences, Statistics or even Social Sciences. However, a degree in Mathematics and Statistics is always an added benefit for enhanced understanding of the concepts.Qualifying with a degree is not the end of the requirements. Brush up your skills by taking online lessons in a special skill set of your choice — get certified on how to use Hadoop, Big Data or R. You can also choose to enroll yourself for a Postgraduate degree in the field of Data Science, Mathematics or any other related field.Remember, learning does not end with earning a degree or certification. You need to practice what you learned — blog and share your knowledge, build an app and explore other avenues and applications of data.The Data Scientists of the modern world have a major role to play in businesses across the globe. They have the ability to extract useful insights from vast amounts of raw data using sophisticated techniques. The business acumen of the Data Scientists help a big deal in predicting what lies ahead for enterprises. The models that the Data Scientists create also bring out measures to mitigate potential threats if any.Take up organizational challenges with ABCDE skillsetAs a Data Scientist, you may have to face challenges while working on projects and finding solutions to problems.A = AnalyticsIf you are a Data Scientist, you are expected not just to study the data and identify the right tools and techniques; you need to have your answers ready to all the questions that come across while you are strategizing on working on a solution with or without a business model.B = Business AcumenOrganizations vouch for candidates with strong business acumen. As a Data Scientist, you are expected to showcase your skills in a way that will make the organization stand one step ahead of the competition. Undertaking a project and working on it is not the end of the path scaled by you. You need to understand and be able to make others understand how your business models influence business outcomes and how the outcomes will prove beneficial to the organization.C = CodingAnd a Data Scientist is expected to be adept at coding too. You may encounter technical issues where you need to sit and work on codes. If you know how to code, it will make you further versatile in confidently assisting your team.D = DomainThe world does not expect Data Scientists to be perfect with knowledge of all domains. However, it is always assumed that a Data Scientist has know-how of various industrial operations. Reading helps as a plus point. You can gain knowledge in various domains by reading the resources online.E = ExplainTo be a successful Data Scientist, you should be able to explain the problem you are faced with to figure out a solution to the problem and share it with the relevant stakeholders. You need to create a difference in the way you explain without leaving any communication gaps.The Important Skills for a Data ScientistLet us now understand the important skills to become an expert Data Scientist – all the skills that go in, to become one. The skills are as follows:Critical thinkingCodingMathML, DL, AICommunication1. Critical thinkingData scientists need to keep their brains racing with critical thinking. They should be able to apply the objective analysis of facts when faced with a complex problem. Upon reaching a logical analysis, a data scientist should formulate opinions or render judgments.Data scientists are counted upon for their understanding of complex business problems and the risks involved with decision-making. Before they plunge into the process of analysis and decision-making, data scientists are required to come up with a 'model' or 'abstract' on what is critical to coming up with the solution to a problem. Data scientists should be able to determine the factors that are extraneous and can be ignored while churning out a solution to a complex business problem.According to Jeffry Nimeroff, CIO at Zeta Global, which provides a cloud-based marketing platform – A data scientist needs to have experience but also have the ability to suspend belief...Before arriving at a solution, it is very important for a Data Scientist to be very clear on what is being expected and if the expected solution can be arrived at. It is only with experience that your intuition works stronger. Experience brings in benefits.If you are a novice and a problem is posed in front of you; all that the one who put the problem in front of you would get is a wide-eyed expression, perhaps. Instead, if you have hands-on experience of working with complex problems no matter what, you will step back, look behind at your experience, draw some inference from multiple points of view and try assessing the problem that is put forth.In simple steps, critical thinking involves the following steps:a. Describe the problem posed in front of you.b. Analyse the arguments involved – The IFs and BUTs.c. Evaluate the significance of the decisions being made and the successes or failures thereafter.2. CodingHandling a complex task might at times call for the execution of a chain of programming tasks. So, if you are a data scientist, you should know how to go about writing code. It does not stop at just writing the code; the code should be executable and should be crucial in helping you find a solution to a complex business problem.In the present scenario, Data Scientists are more inclined towards learning and becoming an expert with Python as the language of choice. There is a substantial crowd following R as well. Scala, Clojure, Java and Octave are a few other languages that find prominence too.Consider the following aspects to be a successful Data Scientist that can dab with programming skills –a) You need to deal with humongous volumes of data.b) Working with real-time data should be like a cakewalk for you.c) You need to hop around cloud computing and work your way with statistical models like the ones shown below:Different Statistical ModelsRegressionOptimizationClusteringDecision treesRandom forestsData scientists are expected to understand and have the ability to code in a bundle of languages – Python, C++ or Java.Gaining the knack to code helps Data Scientists; however, this is not the end requirement. A Data Scientist can always be surrounded by people who code.3. MathIf you have never liked Mathematics as a subject or are not proficient in Mathematics, Data Science is probably not the right career choice for you.You might own an organization or you might even be representing it; the fact is while you engage with your clients, you might have to look into many disparate issues. To deal with the issues that lay in front of you, you will be required to develop complex financial or operational models. To finally be able to build a worthy model, you will end up pulling chunks from large volumes of data. This is where Mathematics helps you.If you have the expertise in Mathematics, building statistical models is easier. Statistical models further help in developing or switching over to key business strategies. With skills in both Mathematics and Statistics, you can get moving in the world of Data Science. Spell the mantra of Mathematics and Statistics onto your lamp of Data Science, lo and behold you can be the genie giving way to the best solutions to the most complex problems.4. Machine learning, Deep Learning, AIData Science overlaps with the fields of Machine Learning, Deep Learning and AI.There is an increase in the way we work with computers, we now have enhanced connectivity; a large amount of data is being collected and industries make use of this data and are moving extremely fast.AI and deep learning may not show up in the requirements of job postings; yet, if you have AI and deep learning skills, you end up eating the big pie.A data scientist needs to be hawk-eyed and alert to the changes in the curve while research is in progress to come up with the best methodology to a problem. Coming up with a model might not be the end. A Data Scientist must be clear as to when to apply which practice to solve a problem without making it more complex.Data scientists need to understand the depth of problems before finding solutions. A data scientist need not go elsewhere to study the problems; all that is there in the data fetched is what is needed to bring out the best solution.A data scientist should be aware of the computational costs involved in building an environment and the following system boundary conditions:a. Interpretabilityb. Latencyc. BandwidthStudying a customer can act as a major plus point for both a data scientist and an orgaStudying nization… This helps in understanding what technology to apply.No matter how generations advance with the use of automated tools and open source is readily available, statistical skills are considered the much-needed add-ons for a data scientist.Understanding statistics is not an easy job; a data scientist needs to be competent to comprehend the assumptions made by the various tools and software.Experts have put forth a few important requisites for data scientists to make the best use of their models:Data scientists need to be handy with proper data interpretation techniques and ought to understand –a. the various functional interfaces to the machine learning algorithmsb. the statistics within the methodsIf you are a data scientist, try dabbing your profile with colours of computer science skills. You must be proficient in working with the keyboard and have a sound knowledge of fundamentals in software engineering.5. CommunicationCommunication and technology show a cycle of operations wherein, there is an integration between people, applications, systems, and data. Data science does not stand separate in this. Working with Data Science is no different. As a Data Scientist, you should be able to communicate with various stakeholders. Data plays a key attribute in the wheel of communication.Communication in Data Science ropes in the ‘storytelling’ ability. This helps you translate a solution you have arrived at into action or intervention that you have put in the pipeline. As a Data Scientist, you should be adept at knitting with the data you have extracted and communicated it clearly to your stakeholders.What does a data scientist communicate to the stakeholders?The benefits of dataThe technology and the computational costs involved in the process of extracting and making use of the dataThe challenges posed in the form of data quality, privacy, and confidentialityA Data Scientist also needs to keep an eye on the wide horizons for better prospects. The organization can be shown a map highlighting other areas of interest that can prove beneficial.If you are a Data Scientist with different feathers in your cap, one being that of a good communicator, you should be able to change a complex form of technical information to a simple and compact form before you present it to the various stakeholders. The information should highlight the challenges, the details of the data, the criteria for success and the anticipated results.If you want to excel in the field of Data Science, you must have an inquisitive bent of mind. The more you ask questions, the more information you gather, the easier it is to come up with paramount business models.6. Data architectureLet us draw some inference from the construction of a building and the role of an architect. Architects have the most knowledge of how the different blocks of buildings can go together and how the different pillars for a block make a strong support system. Like how architects manage and coordinate the entire construction process, so do the Data Scientists while building business models.A Data Scientist needs to understand all that happens to the data from the inception level to when it becomes a model and further until a decision is made based on the model.Not understanding the data architecture can have a tremendous impact on the assumptions made in the process and the decisions arrived at. If a Data Scientist is not familiar with the data architecture, it may lead to the organization taking wrong decisions leading to unexpected and unfavourable results.A slight change within the architecture might lead to situations getting worse for all the involved stakeholders.7. Risk analysis, process improvement, systems engineeringA Data Scientist with sharp business acumen should have the ability to analyse business risks, suggest improvements if any and facilitate further changes in various business processes. As a Data Scientist, you should understand how systems engineering works.If you want to be a Data Scientist and have sharp risk analysis, process improvement and systems engineering skills, you can set yourself for a smooth sail in this vast sea of Data Science.And, rememberYou will no more be a Data Scientist if you stop following scientific theories… After all, Data Science in itself is a major breakthrough in the field of Science.It is always recommended to analyse all the risks that may confront a business before embarking on a journey of model development. This helps in mitigating risks that an organization may have to encounter later. For a smooth business flow, a Data Scientist should also have the nature to probe into the strategies of the various stakeholders and the problems encountered by customers.A Data Scientist should be able to get the picture of the prevailing risks or the various systems that can have a whopping impact on the data or if a model can lead to positive fruition in the form of customer satisfaction.8. Problem-solving and strong business acumenData scientists are not very different when compared to the commoners. We can say this on the lines of problem-solving. The problem solving traits are inherent in every human being. What makes a data scientist stand apart is very good problem-solving skills. We come across complex problems even in everyday situations. How we differ in solving problems is in the perspectives that we apply. Understanding and analyzing before moving on to actually solving the problems by pulling out all the tools in practice is what Data Scientists are good at.The approach that a Data Scientist takes to solve a problem reaps more success than failure. With their approach, they bring critical thinking to the forefront.  Finding a Data Scientist with skill sets at variance is a problem faced by most of the employers.Technical Skills for a Data ScientistWhen the employers are on a hunt to trap the best, they look out for specialization in languages, libraries, and expertise in tech tools. If a candidate comes in with experience, it helps in boosting the profile.Let us see some very important technical skills:PythonRSQLHadoop/Apache SparkJava/SASTableauLet us briefly understand how these languages are in demand.PythonPython is one of the most in-demand languages. This has gained immense popularity as an open-source language. It is widely used both by beginners and experts. Data Scientists need to have Python as one of the primary languages in their kit.RR is altogether a new programming language for statisticians. Anyone with a mathematical bent of mind can learn it. Nevertheless, if you do not appreciate the nuances of Mathematics then it’s difficult to understand R. This never means that you cannot learn it, but without having that mathematical creativity, you cannot harness the power of it.SQLStructured Query Language or SQL is also highly in demand. The language helps in interacting with relational databases. Though it is not of much prominence yet, with a know-how in SQL you can gain a stand in the job market.Hadoop & SparkBoth Hadoop and Spark are open source tools from Apache for big data.Apache Hadoop is an open source software platform. Apache Hadoop helps when you have large data sets on computer clusters built from commodity hardware and you find it difficult to store and process the data sets.Apache Spark is a lightning-fast cluster computing and data processing engine designed for fast computation. It comes with a bunch of development APIs. It supports data workers with efficient execution of streaming, machine learning or SQL workloads.Java & SASWe also have Java and SAS joining the league of languages. These are in-demand languages by large players. Employers offer whopping packages to candidates with expertise in Java and SAS.TableauTableau joins the list as an analytics platform and visualization tool. The tool is powerful and user-friendly. The public version of the tool is available for free. If you wish to keep your data private, you have to consider the costs involved too.Easy tips for a Data ScientistLet us see the in-demand skill set for a Data Scientist in brief.a. A Data Scientist should have the acumen to handle data processing and go about setting models that will help various business processes.b. A Data Scientist should understand the depth of a business problem and the structure of the data that will be used in the process of solving it.c. A Data Scientist should always be ready with an explanation on how the created business models work; even the minute details count.A majority of the crowd out there is good at Maths, Statistics, Engineering or other related subjects. However, when interviewed, they may not show the required traits and when recruited may fail to shine in their performance levels. Sometimes the recruitment process to hire a Data Scientist gets so tedious that employers end up searching with lanterns even in broad daylight. Further, the graphical representation below shows some smart tips for smart Data Scientists.Smart tips for a Data ScientistWhat employers seek the most from Data Scientists?Let us now throw some light into what employers seek the most from Data Scientists:a. A strong sense of analysisb. Machine learning is at the core of what is sought from Data Scientists.c. A Data Scientist should infer and refer to data that has been in practice and will be in practice.d. Data Scientists are expected to be adept at Machine Learning and create models predicting the performance on the basis of demand.e. And, a big NOD to a combo skill set of statistics, Computer Science and Mathematics.Following screenshot shows the requirements of a topnotch employer from a Data Scientist. The requirements were posted on a jobs’ listing website.Let us do a sneak peek into the same job-listing website and see the skills in demand for a Data Scientist.ExampleRecommendations for a Data ScientistWhat are some general recommendations for Data Scientists in the present scenario? Let us walk you through a few.Exhibit your demonstration skills with data analysis and aim to become learned at Machine Learning.Focus on your communication skills. You would have a tough time in your career if you cannot show what you have and cannot communicate what you know. Experts have recommended reading Made to Stick for far-reaching impact of the ideas that you generate.Gain proficiency in deep learning. You must be familiar with the usage, interest, and popularity of deep learning framework.If you are wearing the hat of a Python expert, you must also have the know-how of common python data science libraries – numpy, pandas, matplotlib, and scikit-learn.ConclusionData Science is all about contributing more data to the technologically advanced world. Make your online presence a worthy one; learn while you earn.Start by browsing through online portals. If you are a professional, make your mark on LinkedIn. Securing a job through LinkedIn is now easier than scouring through job sites.Demonstrate all the skills that you are good at on the social portals you are associated with. Suppose you write an article on LinkedIn, do not refrain from sharing the link to the article on your Facebook account.Most important of all – when faced with a complex situation, understand why and what led to the problem. A deeper understanding of a problem will help you come up with the best model. The more you empathize with a situation, the more will be your success count. And in no time, you can become that extraordinary whiz in Data Science.Wishing you immense success if you happen to choose or have already chosen Data Science as the path for your career.All the best for your career endeavour!
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Essential Skills to Become a Data Scientist

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Essential Skills to Become a Data Scientist

The demand for Data Science professionals is now at an all-time high. There are companies in virtually every industry looking to extract the most value from the heaps of information generated on a daily basis.

With the trend for Data Science catching up like never before, organizations are making complete use of their internal data assets to further examine the integration of hundreds of third-party data sources. What is crucial here is the role of the data scientists.

Not very long back, the teams playing the key role of working on the data always found their places in the back rooms of multifold IT organizations. The teams though sitting on the backseat would help in steering the various corporate systems with the required data that acted as the fuel to keep the activities running. The critical database tasks performed by the teams responsible allowed corporate executives to report on operations activities and deliver financial results.

When you take up a career in Data Science, your previous experience or skills do not matter. As a matter of fact, you would need a whole new range of skills to pursue a career in Data Science. Below are the skills required to become a top dog in Data Science.

What should Data Scientists know

what should data scientists know

Data scientists are expected to have knowledge and expertise in the following domains:

The areas arch over dozens of languages, frameworks, and technologies that data scientists need to learn. Data scientists should always have the curiosity to amass more knowledge in their domain so that they stay relevant in this dynamic field.

The world of Data Science demands certain important attributes and skills, according to IT leaders, industry analysts, data scientists, and others.

How to become a Data Scientist?

A majority of Data scientists already have a Master’s degree. If Master’s degree does not quench their thirst for more degrees, some even go on to acquire PhD degrees. Mind you, there are exceptions too. It isn’t mandatory that you should be an expert in a particular subject to become a Data Scientist. You could become one even with a qualification in Computer Science, Physical Sciences, Natural Sciences, Statistics or even Social Sciences. However, a degree in Mathematics and Statistics is always an added benefit for enhanced understanding of the concepts.

Qualifying with a degree is not the end of the requirements. Brush up your skills by taking online lessons in a special skill set of your choice — get certified on how to use Hadoop, Big Data or R. You can also choose to enroll yourself for a Postgraduate degree in the field of Data Science, Mathematics or any other related field.

Remember, learning does not end with earning a degree or certification. You need to practice what you learned — blog and share your knowledge, build an app and explore other avenues and applications of data.

The Data Scientists of the modern world have a major role to play in businesses across the globe. They have the ability to extract useful insights from vast amounts of raw data using sophisticated techniques. The business acumen of the Data Scientists help a big deal in predicting what lies ahead for enterprises. The models that the Data Scientists create also bring out measures to mitigate potential threats if any.

Take up organizational challenges with ABCDE skillset

As a Data Scientist, you may have to face challenges while working on projects and finding solutions to problems.

ABCDE skillset to overcome Organizational Challenges:- Analytics, Business Acumen, Coding, Domain, Explain

A = Analytics

If you are a Data Scientist, you are expected not just to study the data and identify the right tools and techniques; you need to have your answers ready to all the questions that come across while you are strategizing on working on a solution with or without a business model.

B = Business Acumen

Organizations vouch for candidates with strong business acumen. As a Data Scientist, you are expected to showcase your skills in a way that will make the organization stand one step ahead of the competition. Undertaking a project and working on it is not the end of the path scaled by you. You need to understand and be able to make others understand how your business models influence business outcomes and how the outcomes will prove beneficial to the organization.

C = Coding

And a Data Scientist is expected to be adept at coding too. You may encounter technical issues where you need to sit and work on codes. If you know how to code, it will make you further versatile in confidently assisting your team.

D = Domain

The world does not expect Data Scientists to be perfect with knowledge of all domains. However, it is always assumed that a Data Scientist has know-how of various industrial operations. Reading helps as a plus point. You can gain knowledge in various domains by reading the resources online.

E = Explain

To be a successful Data Scientist, you should be able to explain the problem you are faced with to figure out a solution to the problem and share it with the relevant stakeholders. You need to create a difference in the way you explain without leaving any communication gaps.

The Important Skills for a Data Scientist

Let us now understand the important skills to become an expert Data Scientist – all the skills that go in, to become one. The skills are as follows:

The Important Skills for a Data Scientist

  1. Critical thinking
  2. Coding
  3. Math
  4. ML, DL, AI
  5. Communication

1. Critical thinking

Data scientists need to keep their brains racing with critical thinking. They should be able to apply the objective analysis of facts when faced with a complex problem. Upon reaching a logical analysis, a data scientist should formulate opinions or render judgments.

Data scientists are counted upon for their understanding of complex business problems and the risks involved with decision-making. Before they plunge into the process of analysis and decision-making, data scientists are required to come up with a 'model' or 'abstract' on what is critical to coming up with the solution to a problem. Data scientists should be able to determine the factors that are extraneous and can be ignored while churning out a solution to a complex business problem.

According to Jeffry Nimeroff, CIO at Zeta Global, which provides a cloud-based marketing platform – A data scientist needs to have experience but also have the ability to suspend belief...

Before arriving at a solution, it is very important for a Data Scientist to be very clear on what is being expected and if the expected solution can be arrived at. It is only with experience that your intuition works stronger. Experience brings in benefits.

If you are a novice and a problem is posed in front of you; all that the one who put the problem in front of you would get is a wide-eyed expression, perhaps. Instead, if you have hands-on experience of working with complex problems no matter what, you will step back, look behind at your experience, draw some inference from multiple points of view and try assessing the problem that is put forth.

In simple steps, critical thinking involves the following steps:

Steps in critical thinking

a. Describe the problem posed in front of you.

b. Analyse the arguments involved – The IFs and BUTs.

c. Evaluate the significance of the decisions being made and the successes or failures thereafter.

2. Coding

Handling a complex task might at times call for the execution of a chain of programming tasks. So, if you are a data scientist, you should know how to go about writing code. It does not stop at just writing the code; the code should be executable and should be crucial in helping you find a solution to a complex business problem.

In the present scenario, Data Scientists are more inclined towards learning and becoming an expert with Python as the language of choice. There is a substantial crowd following R as well. Scala, Clojure, Java and Octave are a few other languages that find prominence too.

Consider the following aspects to be a successful Data Scientist that can dab with programming skills –

a) You need to deal with humongous volumes of data.

b) Working with real-time data should be like a cakewalk for you.

c) You need to hop around cloud computing and work your way with statistical models like the ones shown below:

Different Statistical Models

  • Regression
  • Optimization
  • Clustering
  • Decision trees
  • Random forests

Data scientists are expected to understand and have the ability to code in a bundle of languages – Python, C++ or Java.

Gaining the knack to code helps Data Scientists; however, this is not the end requirement. A Data Scientist can always be surrounded by people who code.

3. Math

If you have never liked Mathematics as a subject or are not proficient in Mathematics, Data Science is probably not the right career choice for you.

You might own an organization or you might even be representing it; the fact is while you engage with your clients, you might have to look into many disparate issues. To deal with the issues that lay in front of you, you will be required to develop complex financial or operational models. To finally be able to build a worthy model, you will end up pulling chunks from large volumes of data. This is where Mathematics helps you.

If you have the expertise in Mathematics, building statistical models is easier. Statistical models further help in developing or switching over to key business strategies. With skills in both Mathematics and Statistics, you can get moving in the world of Data Science. Spell the mantra of Mathematics and Statistics onto your lamp of Data Science, lo and behold you can be the genie giving way to the best solutions to the most complex problems.

4. Machine learning, Deep Learning, AI

Data Science overlaps with the fields of Machine Learning, Deep Learning and AI.

There is an increase in the way we work with computers, we now have enhanced connectivity; a large amount of data is being collected and industries make use of this data and are moving extremely fast.

AI and deep learning may not show up in the requirements of job postings; yet, if you have AI and deep learning skills, you end up eating the big pie.

A data scientist needs to be hawk-eyed and alert to the changes in the curve while research is in progress to come up with the best methodology to a problem. Coming up with a model might not be the end. A Data Scientist must be clear as to when to apply which practice to solve a problem without making it more complex.

Data scientists need to understand the depth of problems before finding solutions. A data scientist need not go elsewhere to study the problems; all that is there in the data fetched is what is needed to bring out the best solution.

A data scientist should be aware of the computational costs involved in building an environment and the following system boundary conditions:

a. Interpretability

b. Latency

c. Bandwidth

Studying a customer can act as a major plus point for both a data scientist and an orgaStudying nization… This helps in understanding what technology to apply.

No matter how generations advance with the use of automated tools and open source is readily available, statistical skills are considered the much-needed add-ons for a data scientist.

Understanding statistics is not an easy job; a data scientist needs to be competent to comprehend the assumptions made by the various tools and software.

Experts have put forth a few important requisites for data scientists to make the best use of their models:

Data scientists need to be handy with proper data interpretation techniques and ought to understand –

a. the various functional interfaces to the machine learning algorithms

b. the statistics within the methods

If you are a data scientist, try dabbing your profile with colours of computer science skills. You must be proficient in working with the keyboard and have a sound knowledge of fundamentals in software engineering.

5. Communication

Communication and technology show a cycle of operations wherein, there is an integration between people, applications, systems, and data. Data science does not stand separate in this. Working with Data Science is no different. As a Data Scientist, you should be able to communicate with various stakeholders. Data plays a key attribute in the wheel of communication.

Communication in Data Science ropes in the ‘storytelling’ ability. This helps you translate a solution you have arrived at into action or intervention that you have put in the pipeline. As a Data Scientist, you should be adept at knitting with the data you have extracted and communicated it clearly to your stakeholders.

What does a data scientist communicate to the stakeholders?

What does a data scientist communicate to the stakeholders

The benefits of data

The technology and the computational costs involved in the process of extracting and making use of the data

The challenges posed in the form of data quality, privacy, and confidentiality

A Data Scientist also needs to keep an eye on the wide horizons for better prospects. The organization can be shown a map highlighting other areas of interest that can prove beneficial.

If you are a Data Scientist with different feathers in your cap, one being that of a good communicator, you should be able to change a complex form of technical information to a simple and compact form before you present it to the various stakeholders. The information should highlight the challenges, the details of the data, the criteria for success and the anticipated results.

If you want to excel in the field of Data Science, you must have an inquisitive bent of mind. The more you ask questions, the more information you gather, the easier it is to come up with paramount business models.

6. Data architecture

Let us draw some inference from the construction of a building and the role of an architect. Architects have the most knowledge of how the different blocks of buildings can go together and how the different pillars for a block make a strong support system. Like how architects manage and coordinate the entire construction process, so do the Data Scientists while building business models.

A Data Scientist needs to understand all that happens to the data from the inception level to when it becomes a model and further until a decision is made based on the model.

Not understanding the data architecture can have a tremendous impact on the assumptions made in the process and the decisions arrived at. If a Data Scientist is not familiar with the data architecture, it may lead to the organization taking wrong decisions leading to unexpected and unfavourable results.

A slight change within the architecture might lead to situations getting worse for all the involved stakeholders.

7. Risk analysis, process improvement, systems engineering

A Data Scientist with sharp business acumen should have the ability to analyse business risks, suggest improvements if any and facilitate further changes in various business processes. As a Data Scientist, you should understand how systems engineering works.

If you want to be a Data Scientist and have sharp risk analysis, process improvement and systems engineering skills, you can set yourself for a smooth sail in this vast sea of Data Science.

And, remember

You will no more be a Data Scientist if you stop following scientific theories… After all, Data Science in itself is a major breakthrough in the field of Science.

It is always recommended to analyse all the risks that may confront a business before embarking on a journey of model development. This helps in mitigating risks that an organization may have to encounter later. For a smooth business flow, a Data Scientist should also have the nature to probe into the strategies of the various stakeholders and the problems encountered by customers.

A Data Scientist should be able to get the picture of the prevailing risks or the various systems that can have a whopping impact on the data or if a model can lead to positive fruition in the form of customer satisfaction.

8. Problem-solving and strong business acumen

Data scientists are not very different when compared to the commoners. We can say this on the lines of problem-solving. The problem solving traits are inherent in every human being. What makes a data scientist stand apart is very good problem-solving skills. We come across complex problems even in everyday situations. How we differ in solving problems is in the perspectives that we apply. Understanding and analyzing before moving on to actually solving the problems by pulling out all the tools in practice is what Data Scientists are good at.

The approach that a Data Scientist takes to solve a problem reaps more success than failure. With their approach, they bring critical thinking to the forefront.  

Finding a Data Scientist with skill sets at variance is a problem faced by most of the employers.

Technical Skills for a Data ScientistTechnical or Programming Skills required to become a Data Scientist

When the employers are on a hunt to trap the best, they look out for specialization in languages, libraries, and expertise in tech tools. If a candidate comes in with experience, it helps in boosting the profile.

Let us see some very important technical skills:

  • Python
  • R
  • SQL
  • Hadoop/Apache Spark
  • Java/SAS
  • Tableau

Let us briefly understand how these languages are in demand.

Python

Python is one of the most in-demand languages. This has gained immense popularity as an open-source language. It is widely used both by beginners and experts. Data Scientists need to have Python as one of the primary languages in their kit.

R

R is altogether a new programming language for statisticians. Anyone with a mathematical bent of mind can learn it. Nevertheless, if you do not appreciate the nuances of Mathematics then it’s difficult to understand R. This never means that you cannot learn it, but without having that mathematical creativity, you cannot harness the power of it.

SQL

Structured Query Language or SQL is also highly in demand. The language helps in interacting with relational databases. Though it is not of much prominence yet, with a know-how in SQL you can gain a stand in the job market.

Hadoop & Spark

Both Hadoop and Spark are open source tools from Apache for big data.

Apache Hadoop is an open source software platform. Apache Hadoop helps when you have large data sets on computer clusters built from commodity hardware and you find it difficult to store and process the data sets.

Apache Spark is a lightning-fast cluster computing and data processing engine designed for fast computation. It comes with a bunch of development APIs. It supports data workers with efficient execution of streaming, machine learning or SQL workloads.

Java & SAS

We also have Java and SAS joining the league of languages. These are in-demand languages by large players. Employers offer whopping packages to candidates with expertise in Java and SAS.

Tableau

Tableau joins the list as an analytics platform and visualization tool. The tool is powerful and user-friendly. The public version of the tool is available for free. If you wish to keep your data private, you have to consider the costs involved too.

Easy tips for a Data Scientist

Let us see the in-demand skill set for a Data Scientist in brief.

a. A Data Scientist should have the acumen to handle data processing and go about setting models that will help various business processes.

b. A Data Scientist should understand the depth of a business problem and the structure of the data that will be used in the process of solving it.

c. A Data Scientist should always be ready with an explanation on how the created business models work; even the minute details count.

A majority of the crowd out there is good at Maths, Statistics, Engineering or other related subjects. However, when interviewed, they may not show the required traits and when recruited may fail to shine in their performance levels. Sometimes the recruitment process to hire a Data Scientist gets so tedious that employers end up searching with lanterns even in broad daylight. Further, the graphical representation below shows some smart tips for smart Data Scientists.

Smart tips for a Data Scientist

Smart tips for a Data Scientist

What employers seek the most from Data Scientists?

Let us now throw some light into what employers seek the most from Data Scientists:

a. A strong sense of analysis

b. Machine learning is at the core of what is sought from Data Scientists.

c. A Data Scientist should infer and refer to data that has been in practice and will be in practice.

d. Data Scientists are expected to be adept at Machine Learning and create models predicting the performance on the basis of demand.

e. And, a big NOD to a combo skill set of statistics, Computer Science and Mathematics.

Following screenshot shows the requirements of a topnotch employer from a Data Scientist. The requirements were posted on a jobs’ listing website.

Let us do a sneak peek into the same job-listing website and see the skills in demand for a Data Scientist.

  1. Example

Essential Skills to become a Data Scientist

Recommendations for a Data Scientist

What are some general recommendations for Data Scientists in the present scenario? Let us walk you through a few.

  • Exhibit your demonstration skills with data analysis and aim to become learned at Machine Learning.
  • Focus on your communication skills. You would have a tough time in your career if you cannot show what you have and cannot communicate what you know. Experts have recommended reading Made to Stick for far-reaching impact of the ideas that you generate.
  • Gain proficiency in deep learning. You must be familiar with the usage, interest, and popularity of deep learning framework.

If you are wearing the hat of a Python expert, you must also have the know-how of common python data science libraries – numpy, pandas, matplotlib, and scikit-learn.

Conclusion

Data Science is all about contributing more data to the technologically advanced world. Make your online presence a worthy one; learn while you earn.

Start by browsing through online portals. If you are a professional, make your mark on LinkedIn. Securing a job through LinkedIn is now easier than scouring through job sites.

Demonstrate all the skills that you are good at on the social portals you are associated with. Suppose you write an article on LinkedIn, do not refrain from sharing the link to the article on your Facebook account.

Most important of all – when faced with a complex situation, understand why and what led to the problem. A deeper understanding of a problem will help you come up with the best model. The more you empathize with a situation, the more will be your success count. And in no time, you can become that extraordinary whiz in Data Science.

Wishing you immense success if you happen to choose or have already chosen Data Science as the path for your career.

All the best for your career endeavour!

Priyankur

Priyankur Sarkar

Data Science Enthusiast

Priyankur Sarkar loves to play with data and get insightful results out of it, then turn those data insights and results in business growth. He is an electronics engineer with a versatile experience as an individual contributor and leading teams, and has actively worked towards building Machine Learning capabilities for organizations.

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1 comments

Juhi 18 Jun 2019

It’s really great information. Keep sharing, Thanks

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What is K-Nearest Neighbor in Machine Learning: K-NN Algorithm

If you are thinking of a simple, easy-to-implement supervised machine learning algorithm which can be used to solve both classification as well as regression problems, K-Nearest Neighbor (K-NN) is the perfect choice. Learning K-NN is a great way to introduce yourself to machine learning and classification in general. Also, you will find a lot of intense application of K-NN in data mining, pattern recognition, semantic searching, intrusion detection and anomaly detection.K-Nearest Neighbors is one of the most basic supervised machine learning algorithms, yet very essential. A supervised machine learning algorithm is one of the types of machine learning algorithm which is dependent on labelled input data in order to learn a function which is capable of producing an output whenever a new unlabeled data is given as input.In real life scenarios, K-NN is widely used as it is non-parametric which means it does not make any underlying assumptions about the distributions of data. With the business world entirely revolving around Data Science, it has become one of the most lucrative fields. Hence, the heavy demand for a Data Science Certification.Parametric vs Non-parametric MethodsLet us look into how different is a parametric machine learning algorithm from a nonparametric machine learning algorithm.Machine learning, in other words can be called as learning a function (f) which maps input variables (X) to the output variables (Y).Y=f(X)An algorithm learns about the target mapping function from the training data. As we are unaware of the form of the function, we have to evaluate various machine learning algorithms and figure out which algorithms perform better at providing an approximation of the underlying function.Statistical Methods are classified on the basis of what we know about the population we are studying.Parametric statistics is a branch of statistics which assumes that sample data comes from a population that follows a probability distribution based on a fixed set of parameters.Nonparametric statistics is the branch of statistics that is not based solely on population parameters.Parametric Machine Learning AlgorithmsThis particular algorithm involves two steps:Selecting a form for the functionLearning the coefficients for the function from the training dataLet us consider a line to understand functional form for the mapping function as it is used in linear regression and simplify the learning process.b0 + b1*x1 + b2*x2 = 0Where b0, b1 and b2 are the coefficients of the line which control the intercept and slope, and x1 and x2 are two input variables.All we have to do now is to estimate the coefficients of the line equation to get a predictive model for the problem. Now, the problem is that the actual unknown underlying function may not be a linear function like a line. In that case, the approach will give poor results. Some of the examples of parametric machine learning algorithms are mentioned below:Logistic RegressionLinear Discriminant AnalysisPerceptronNaive BayesSimple Neural NetworksNonparametric Machine Learning AlgorithmsNonparametric methods always try to find the best fit training data while constructing the mapping function which also allows it to fit a large number of functional forms. Some of the examples of nonparametric machine learning algorithms are mentioned below:k-Nearest NeighborsDecision Trees like CART and C4.5Support Vector MachinesThe best example of nonparametric machine learning algorithms would be k-nearest neighbors algorithm which makes predictions based on the k most similar training patterns for a given set of new data instance. This method simply assumes that the patterns which are close are likely to be of similar type.Parametric Machine Learning AlgorithmsNonparametric Machine Learning AlgorithmsBenefitsSimple to understand and interpret resultsSpeed of learning from data in fastLess training data is requiredFlexible enough to fit a large number of functional formsNo assumptions about the underlying functionsProvides high performance for predictionLimitationsChoosing a functional form constrains the method to the specified formIt has limited complexity and more suited to simpler problemsIt is unlikely to match the underlying mapping function and results in poor fitRequires more training data in order to estimate the mapping functionDue to more parameters to train, it is slower comparativelyThere is a risk to overfit the training dataMethod Based LearningThere are several learning models namely:Association rules basedEnsemble method basedDeep Learning basedClustering method basedRegression Analysis basedBayesian method basedDimensionality reduction basedKernel method basedInstance basedLet us understand what Instance Based Learning is all about.Instance Based Learning (IBL)Instance-Based methods are the simplest form of learningInstance -Based learning is lazy learningK-NN model works on identified instanceInstances are retrieved from memory and then this data is used to classify the new query instanceInstance based learning is also called memory-based or case-basedUnder Instance-based Learning we have,Nearest-neighbor classifierUses k “closest” points (nearest neighbors) for performing classification. For example: It’s how people judge by observing our peers. We tend to move with people of similar attributes.Lazy Learning vs Eager LearningLazy LearningEager LearningSimply stores the training data and waits until it is given a test tuple.Munges the training data as soon as it receives it.It's slow as it calculates based on the current data set instead of coming up with an algorithm based on historical data.It's fast as it has pre-calculated algorithm.Localized data so generalization takes time at every iteration.On the basis of training set ,it constructs a classification model before receiving new data to classify.What is K-NN?One of the biggest applications of K-Nearest Neighbor search is Recommender Systems. If you have noticed while you are shopping as a user on Amazon and you like a particular item, you are recommended with similar items.It also recommends similar items bought by other users and other set of items which are often bought together. Basically, the algorithm compares the set of users who like each item and looks for similarity. This not only applies to recommending items or products but also recommending media and even advertisements to display to a user.K nearest neighbors or K-NN Algorithm is a simple algorithm which uses the entire dataset in its training phase. Whenever a prediction is required for an unseen data instance, it searches through the entire training dataset for k-most similar instances and the data with the most similar instance is finally returned as the prediction.This algorithm suggests that if you’re similar to your neighbours, then you are one of them. Let us consider a simple example, if apple looks more similar to peach, pear, and cherry (fruits) than monkey, cat or a rat (animals), then most likely apple is a fruit.Nearest Neighbours algorithm has been in action for the last sixty years. It is mainly used in statistical estimation and pattern recognition, as a non-parametric method, for regression and classification. The main aim of the K-Nearest Neighbor algorithm is to classify a new data point by comparing it to all previously seen data points. The classification of the k most similar previous cases are used for predicting the classification of the current data point. It is a simple algorithm which stores all available cases and classifies new cases based on a similarity measure (e.g., distance functions).When do we use K-NN algorithm?K-NN algorithm can be used for applications which require high accuracy as it makes highly accurate predictions. The quality of predictions is completely dependent on the distance measure. Thus, this algorithm is suitable for applications for which you have sufficient domain knowledge so that it can help you select an appropriate measure.As we have already seen K-NN algorithm is a type of lazy learning, the computation for the generation is postponed until classification which indeed increases the costs of computation compared to other machine learning algorithms. But still K-NN is considered to be the better choice for applications where accuracy is more important and predictions are not requested frequently.K-NN can be used for both regression and classification predictive problems. However, in the industry it is mostly used in classification problems.Generally we mainly look at 3 important aspects in order to evaluate any technique:Ease to interpret outputCalculation timePredictive PowerLet us consider a few examples to place K-NN in the scale :If you notice the chart mentioned above, K-NN algorithm exceeds in most of the parameters. It is most commonly used for ease of interpretation and low calculation time.How does the K-NN algorithm work?K-NN algorithm works on the basis of feature similarity. The classification of a given data point is determined by how closely out-of-sample features resemble our training set.The above figure shows an example of k-NN classification. If you consider the nearest neighbor to the test sample, it is a blue square (Class 1) and k=1. This falls inside the inner circle.Now, if you consider k=3, then you will see 2 red triangles and only 1 blue square falls under the outer circle. Thus, the test sample is classified as a red triangle now (Class 2).Similarly, if you consider k=5, it is assigned to the first class (3 squares vs. 2 triangles outside the outer circle).K-NN in RegressionIn regression problems, K-NN is used for prediction based on the mean or the median of the K-most similar instances.K-NN in ClassificationK-nearest-neighbor classification was actually developed from the need to perform discriminant analysis when reliable parametric estimates of probability densities are unknown or are difficult to determine. When K-NN is used for classification, the output is easily calculated by the class having the highest frequency from the K-most similar instances. The class with maximum vote is taken into consideration for prediction.The probabilities of Classes can be calculated as the normalized frequency of samples that belong to each class in the set of K most similar instances for a new data instance.For example, in a binary classification problem (class is 0 or 1):p(class=0) = count(class=0) / (count(class=0)+count(class=1))If you are using K and you have an even number of classes (e.g. 2) it is a good idea to choose a K value with an odd number to avoid a tie. And the inverse, use an even number for K when you have an odd number of classes.Ties can be broken consistently by expanding K by 1 and looking at the class of the next most similar instance in the training dataset.Making Predictions with K-NNA case can be classified by a majority vote of its neighbors. The case is then assigned to the most common class amongst its K nearest neighbors measured by a distance function. Suppose the value of K is 1, then the case is simply assigned to the class of its nearest neighbor.The three distance measures mentioned above are valid only for continuous variables. For categorical variables, the Hamming distance is used. It also brings up the issue of standardization of the numerical variables between 0 and 1 when there is a mixture of numerical and categorical variables in the dataset.By inspecting the data, you can choose the best optimal value for K. Generally, a large value of K is more accurate as it tends to reduce the overall noise but is not always true. Another way to retrospectively determine a good K value by using an independent dataset to validate the K value is Cross-validation. According to observation, the optimal K for most datasets has been between 3-10 which provides better results than 1NN.For example, let us consider an example where the data mentioned below us concerned with credit default. Age and Loan are two numerical variables (predictors) and Default is the target.By observing the data mentioned above, we can use the training set in order to classify an unknown case (Age=48 and Loan=$142,000) using Euclidean distance. If K=1 then the nearest neighbor is the last case in the training set with Default=Y.AgeLoanDefaultDistance25$40,000N10200035$60,000N8200045$80,000N6200020$20,000N12200035$120,000N22000252$18,000N12400023$95,000Y4700040$62,000Y8000060$100,000Y42000348$220,000Y7800033$150,000Y8000148$142,000?Euclidean DistanceWith K=3, there are two Default=Y and one Default=N out of three closest neighbors. The prediction for the unknown case is again Default=Y.Standardized DistanceOne major drawback in calculating distance measures directly from the training set is in the case where variables have different measurement scales or there is a mixture of numerical and categorical variables. For example, if one variable is based on annual income in dollars, and the other is based on age in years then income will have a much higher influence on the distance calculated. One solution is to standardize the training set as shown below.AgeLoanDefaultDistance0.1250.11N0.76520.3750.21N0.52000.6250.31N0.316000.01N0.92450.3750.50N0.34280.80.00N0.62200.0750.38Y0.66690.50.22Y0.443710.41Y0.36500.71.00Y0.38610.3250.65Y0.37710.70.61?Standardized VariableUsing the standardized distance on the same training set, the unknown case returned a different neighbor which is not a good sign of robustness.Between-sample geometric distanceThe k-nearest-neighbor classifier is commonly based on the Euclidean distance between a test sample and the specified training samples. Let  xi be an input sample with p features, (xi1, xi2, …, xip), n be the total number of input samples (i=1,2,…,n) and p the total number of features (j=1,2,…,p) . The Euclidean distance between sample xi and xl (l=1,2,…,n) is defined as:A graphical representation of the nearest neighbor concept is illustrated in the Voronoi tessellation. The tessellation shows 19 samples marked with a "+", and the Voronoi cell, R, surrounding each sample. A Voronoi cell encapsulates all neighboring points that are nearest to each sample and is defined as:Where Ri is the Voronoi cell for sample xi, and x represents all possible points within Voronoi cell Ri.Voronoi tessellation showing Voronoi cells of 19 samples marked with a "+"The Voronoi tessellation reflects two characteristics of the example 2-dimensional coordinate system: i) all possible points within a sample's Voronoi cell are the nearest neighboring points for that sample, and ii) for any sample, the nearest sample is determined by the closest Voronoi cell edge.According to the latter characteristic, the k-nearest-neighbor classification rule is to assign to a test sample the majority category label of its k nearest training samples. In practice, k is usually chosen to be odd, so as to avoid ties. The k = 1 rule is generally called the nearest-neighbor classification rule.Curse of DimensionalityThe curse of dimensionality refers to various phenomena that are witnessed while analyzing and organizing data in high-dimensional spaces (often with hundreds or thousands of dimensions). Such phenomenon do not occur in low-dimensional settings such as the three-dimensional physical space of everyday experience.K-NN algorithm will work absolutely fine when you are dealing with a small number of input variables (p)  but will struggle when there are a large number of inputs.K-NN works well with a small number of input variables (p), but struggles when the number of inputs is very large. Each input variable can be considered a dimension of a p-dimensional input space. For example, suppose you have two input variables x1 and x2, the input space would be 2-dimensional. With the increase in the number of dimensions, the volume of the input space increases at an exponential rate.In case of higher dimensions, the points which are similar may have large distances. All these points will be then away from each other and our intuition about 2 to 3 dimensional spaces will not be applicable. This kind of problem is called the “Curse of Dimensionality“. How is K in K-means different from K in K-NN?K-Means Clustering and k-Nearest Neighbors algorithm, both are commonly used algorithms in Machine Learning. They are often confused with each other, especially when we are talking about the k-factor. The ‘K’ in K-Means Clustering has nothing to do with the ‘K’ in K-NN algorithm. k-Means Clustering is an unsupervised learning algorithm that is used for clustering whereas K-NN is a supervised learning algorithm used for classification.K-Means AlgorithmThe k-means algorithm is an unsupervised clustering algorithm which takes a couple of unlabeled points and then groups them into “k” number of clusters.The “k” in k-means denotes the number of clusters you would like to have in the end. Suppose the value of k is 5, it means you will have 5 clusters on the data set.Let us see how it works.Step 1: First you determine the value of K by Elbow method and then specify the number of clusters KStep 2: Next you have to randomly assign each data point to a clusterStep 3: Determine the cluster centroid coordinatesStep 4: Determine the distances of each data point to the centroids and re-assign each point to the closest cluster centroid based upon minimum distanceStep 5: Calculate cluster centroids againStep 6: Repeat steps 4 and 5 until we reach global optima where further improvements are not possible and there is no provision to switch data points from one cluster to another.Implementation in Python#Finding the optimum number of clusters for k-means clustering Nc = range(1, 10) kmeans = [KMeans(n_clusters=i) for i in Nc] kmeans score = [kmeans[i].fit(x).score(x) for i in range(len(kmeans))] score pl.plot(Nc,score) pl.xlabel('Number of Clusters') pl.ylabel('Score') pl.title('Elbow Curve') pl.show()You can clearly see why it is called 'The elbow method' from the above graph, the optimum clusters is where the elbow occurs.Now that we have the optimum amount of clusters (k=3), we can move on to applying K-means clustering to the Iris dataset.#Implementation of K-Means Clustering model = KMeans(n_clusters = 3) model.fit(x) model.labels_ colormap = np.array(['Red', 'Blue', 'Green']) z = plt.scatter(x.sepal_length, x.sepal_width, x.petal_length, c = colormap[model.labels_])#Accuracy of K-Means Clustering accuracy_score(iris.target,model.labels_) 0.8933333333333333K-NN AlgorithmBy now, we already know that K-NN algorithm is a supervised classification algorithm. It takes into consideration a couple of labelled points and then uses those points to learn how to label other points. To be able to assign label to other points, K-NN algorithm looks for the closest neighbor of the new point and checks for voting. The most number of neighbors around the new point decide the label of the new point.The “k” in K-Nearest Neighbors is the number of neighbors it checks. It is supervised because it is trying to classify a point on the basis of the known classification of other points.Let us see how it works.Step 1: Firstly, you determine the value for K.Step 2: Then you calculate the distances between the new input (test data) and all the training data. The most commonly used metrics for calculating distance are Euclidean, Manhattan and MinkowskiStep 3: Sort the distance and determine k nearest neighbors based on minimum distance valuesStep 4: Analyze the category of those neighbors and assign the category for the test data based on majority voteStep 5: Return the predicted classImplementation using Pythonerror = [] # Calculating error for K values between 1 and 40 for i in range(1, 40): K-NN = KNeighborsClassifier(n_neighbors=i) K-NN.fit(X_train, y_train) pred_i = K-NN.predict(X_test) error.append(np.mean(pred_i != y_test)) plt.figure(figsize=(12, 6)) plt.plot(range(1, 40), error, color='black', linestyle='dashed', marker='o',     markerfacecolor='grey', markersize=10) plt.title('Error Rate K Value') plt.xlabel('K Value') plt.ylabel('Mean Error') Text(0, 0.5, 'Mean Error')Now we know for what values of ‘K’, the error rate will be less. Let’s fix k=5 and implement K-NN algorithm.#Creating training and test splits from sklearn.model_selection import train_test_split X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.20) #Performing Feature Scaling from sklearn.preprocessing import StandardScaler scaler = StandardScaler() scaler.fit(X_train) X_train = scaler.transform(X_train) X_test = scaler.transform(X_test) #Training K-NN with k=5 from sklearn.neighbors import KNeighborsClassifier classifier = KNeighborsClassifier(n_neighbors=5) classifier.fit(X_train, y_train) KNeighborsClassifier(algorithm='auto', leaf_size=30, metric='minkowski',                     metric_params=None, n_jobs=None, n_neighbors=5, p=2,                     weights='uniform') y_pred = classifier.predict(X_test) from sklearn.metrics import classification_report, confusion_matrix print(confusion_matrix(y_test, y_pred)) print(classification_report(y_test, y_pred)) [[10  0  0] [ 0  9  2] [ 0  1  8]]                 precision recall   f1-score   support     Iris-setosa        1.00         1.00       1.00       10 Iris-versicolor       0.90       0.82     0.86       11 Iris-virginica     0.80         0.89       0.84       9       accuracy                   0.90         30       macro avg     0.90       0.90     0.90     30   weighted avg    0.90       0.90     0.90       30Practical Applications of K-NNNow that we have we have seen how K-NN works, let us look into some of the practical applications of K-NN.Recommending products to people with similar interests, recommending movies and TV shows as per viewer’s choice and interest, recommending hotels and other accommodation facilities while you are travelling based on your previous bookings.Assigning credit ratings based on financial characteristics, comparing people with similar financial features in a database. By analyzing the nature of a credit rating, people with similar financial details, they would be assigned similar credit ratings.Should the bank give a loan to an individual? Would an individual default on his or her loan? Is that person closer in characteristics to people who defaulted or did not default on their loans?Some advanced examples could include handwriting detection (like OCR), image recognition and even video recognition.Some pros and cons of K-NNProsTraining phase of K-nearest neighbor classification is faster in comparison with other classification algorithms.Training of a model is not required for generalization.Simple algorithm — to explain and understand/interpret.High accuracy (relatively) — it is pretty high but not competitive in comparison to better supervised learning models.K-NN can be useful in case of nonlinear data.Versatile — useful for classification or regression.ConsTesting phase of K-nearest neighbor classification is slower and costlier with respect to time and memory. High memory requirement - Requires large memory for storing the entire training dataset.K-NN requires scaling of data because K-NN uses the Euclidean distance between two data points to find nearest neighbors.Euclidean distance is sensitive to magnitudes. The features with high magnitudes will weigh more than features with low magnitudes.Not suitable for large dimensional data.How to improve the performance of K-NN?Rescaling Data: K-NN performs much better if all of the data has the same scale. Normalizing your data to the range [0, 1] is a good idea. It may also be a good idea to standardize your data if it has a Gaussian distribution.Addressing Missing Data: Missing data will mean that the distance between samples can not be calculated. These samples could be excluded or the missing values could be imputed.Reducing Dimensionality: K-NN is suited for lower dimensional data. You can try it on high dimensional data (hundreds or thousands of input variables) but be aware that it may not perform as good as other techniques. K-NN can benefit from feature selection that reduces the dimensionality of the input feature space.In this article we have learned about the K-Nearest Neighbor algorithm, where we should use it, how it works and so on. Also, we have discussed about parametric and nonparametric machine learning algorithms, instance based learning, eager and lazy learning, advantages and disadvantages of using K-NN, performance improvement suggestions and have implemented K-NN in Python. To learn more about other machine learning algorithms, join our Data Science Certification course and expand your learning skill set and career opportunities.
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What is K-Nearest Neighbor in Machine Learning: K-...

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What is Linear Regression in Machine Learning

Machine Learning, being a subset of Artificial Intelligence (AI), has been playing a dominant role in our daily lives. Data science engineers and developers working in various domains are widely using machine learning algorithms to make their tasks simpler and life easier. For example, certain machine learning algorithms enable Google Maps to find the fastest route to our destinations, allow Tesla to make driverless cars, help Amazon to generate almost 35% of their annual income, AccuWeather to get the weather forecast of 3.5 million locations weeks in advance, Facebook to automatically detect faces and suggest tags and so on.In statistics and machine learning, linear regression is one of the most popular and well understood algorithms. Most data science enthusiasts and machine learning  fanatics begin their journey with linear regression algorithms. In this article, we will look into how linear regression algorithm works and how it can be efficiently used in your machine learning projects to build better models.Linear Regression is one of the machine learning algorithms where the result is predicted by the use of known parameters which are correlated with the output. It is used to predict values within a continuous range rather than trying to classify them into categories. The known parameters are used to make a continuous and constant slope which is used to predict the unknown or the result.What is a Regression Problem?Majority of the machine learning algorithms fall under the supervised learning category. It is the process where an algorithm is used to predict a result based on the previously entered values and the results generated from them. Suppose we have an input variable ‘x’ and an output variable ‘y’ where y is a function of x (y=f{x}). Supervised learning reads the value of entered variable ‘x’ and the resulting variable ‘y’ so that it can use those results to later predict a highly accurate output data of ‘y’ from the entered value of ‘x’. A regression problem is when the resulting variable contains a real or a continuous value. It tries to draw the line of best fit from the data gathered from a number of points.For example, which of these is a regression problem?How much gas will I spend if I drive for 100 miles?What is the nationality of a person?What is the age of a person?Which is the closest planet to the Sun?Predicting the amount of gas to be spent and the age of a person are regression problems. Predicting nationality is categorical and the closest planet to the Sun is discrete.What is Linear Regression?Let’s say we have a dataset which contains information about the relationship between ‘number of hours studied’ and ‘marks obtained’. A number of students have been observed and their hours of study along with their grades are recorded. This will be our training data. Our goal is to design a model that can predict the marks if number of hours studied is provided. Using the training data, a regression line is obtained which will give minimum error. This linear equation is then used to apply for a new data. That is, if we give the number of hours studied by a student as an input, our model should be able to predict their mark with minimum error.Hypothesis of Linear RegressionThe linear regression model can be represented by the following equation:where,Y is the predicted valueθ₀ is the bias term.θ₁,…,θn are the model parametersx₁, x₂,…,xn are the feature values.The above hypothesis can also be represented byWhere, θ is the model’s parameter vector including the bias term θ₀; x is the feature vector with x₀ =1Y (pred) = b0 + b1*xThe values b0 and b1 must be chosen so that the error is minimum. If sum of squared error is taken as a metric to evaluate the model, then the goal is to obtain a line that best reduces the error.If we don’t square the error, then the positive and negative points will cancel each other out.For a model with one predictor,Exploring ‘b1’If b1 > 0, then x (predictor) and y(target) have a positive relationship. That is an increase in x will increase y.If b1 < 0, then x (predictor) and y(target) have a negative relationship. That is an increase in x will decrease y.Exploring ‘b0’If the model does not include x=0, then the prediction will become meaningless with only b0. For example, we have a dataset that relates height(x) and weight(y). Taking x=0 (that is height as 0), will make the equation have only b0 value which is completely meaningless as in real-time height and weight can never be zero. This resulted due to considering the model values beyond its scope.If the model includes value 0, then ‘b0’ will be the average of all predicted values when x=0. But, setting zero for all the predictor variables is often impossible.The value of b0 guarantees that the residual will have mean zero. If there is no ‘b0’ term, then the regression will be forced to pass over the origin. Both the regression coefficient and prediction will be biased.How does Linear Regression work?Let’s look at a scenario where linear regression might be useful: losing weight. Let us consider that there’s a connection between how many calories you take in and how much you weigh; regression analysis can help you understand that connection. Regression analysis will provide you with a relation which can be visualized into a graph in order to make predictions about your data. For example, if you’ve been putting on weight over the last few years, it can predict how much you’ll weigh in the next ten years if you continue to consume the same amount of calories and burn them at the same rate.The goal of regression analysis is to create a trend line based on the data you have gathered. This then allows you to determine whether other factors apart from the amount of calories consumed affect your weight, such as the number of hours you sleep, work pressure, level of stress, type of exercises you do etc. Before taking into account, we need to look at these factors and attributes and determine whether there is a correlation between them. Linear Regression can then be used to draw a trend line which can then be used to confirm or deny the relationship between attributes. If the test is done over a long time duration, extensive data can be collected and the result can be evaluated more accurately. By the end of this article we will build a model which looks like the below picture i.e, determine a line which best fits the data.How do we determine the best fit line?The best fit line is considered to be the line for which the error between the predicted values and the observed values is minimum. It is also called the regression line and the errors are also known as residuals. The figure shown below shows the residuals. It can be visualized by the vertical lines from the observed data value to the regression line.When to use Linear Regression?Linear Regression’s power lies in its simplicity, which means that it can be used to solve problems across various fields. At first, the data collected from the observations need to be collected and plotted along a line. If the difference between the predicted value and the result is almost the same, we can use linear regression for the problem.Assumptions in linear regressionIf you are planning to use linear regression for your problem then there are some assumptions you need to consider:The relation between the dependent and independent variables should be almost linear.The data is homoscedastic, meaning the variance between the results should not be too much.The results obtained from an observation should not be influenced by the results obtained from the previous observation.The residuals should be normally distributed. This assumption means that the probability density function of the residual values is normally distributed at each independent value.You can determine whether your data meets these conditions by plotting it and then doing a bit of digging into its structure.Few properties of Regression LineHere are a few features a regression line has:Regression passes through the mean of independent variable (x) as well as mean of the dependent variable (y).Regression line minimizes the sum of “Square of Residuals”. That’s why the method of Linear Regression is known as “Ordinary Least Square (OLS)”. We will discuss more in detail about Ordinary Least Square later on.B1 explains the change in Y with a change in x  by one unit. In other words, if we increase the value of ‘x’ it will result in a change in value of Y.Finding a Linear Regression lineLet’s say we want to predict ‘y’ from ‘x’ given in the following table and assume they are correlated as “y=B0+B1∗x”xyPredicted 'y'12Β0+B1∗121Β0+B1∗233Β0+B1∗346Β0+B1∗459Β0+B1∗5611Β0+B1∗6713Β0+B1∗7815Β0+B1∗8917Β0+B1∗91020Β0+B1∗10where,Std. Dev. of x3.02765Std. Dev. of y6.617317Mean of x5.5Mean of y9.7Correlation between x & y0.989938If the Residual Sum of Square (RSS) is differentiated with respect to B0 & B1 and the results equated to zero, we get the following equation:B1 = Correlation * (Std. Dev. of y/ Std. Dev. of x)B0 = Mean(Y) – B1 * Mean(X)Putting values from table 1 into the above equations,B1 = 2.64B0 = -2.2Hence, the least regression equation will become –Y = -2.2 + 2.64*xxY - ActualY - Predicted120.44213.08335.72468.36591161113.6471316.2881518.9291721.56102024.2As there are only 10 data points, the results are not too accurate but if we see the correlation between the predicted and actual line, it has turned out to be very high; both the lines are moving almost together and here is the graph for visualizing our predicted values:Model PerformanceAfter the model is built, if we see that the difference in the values of the predicted and actual data is not much, it is considered to be a good model and can be used to make future predictions. The amount that we consider “not much” entirely depends on the task you want to perform and to what percentage the variation in data can be handled. Here are a few metric tools we can use to calculate error in the model-R – Square (R2)Total Sum of Squares (TSS): total sum of squares (TSS) is a quantity that appears as part of a standard way of presenting results of such an analysis. Sum of squares is a measure of how a data set varies around a central number (like the mean). The Total Sum of Squares tells how much variation there is in the dependent variable.TSS = Σ (Y – Mean[Y])2Residual Sum of Squares (RSS): The residual sum of squares tells you how much of the dependent variable’s variation your model did not explain. It is the sum of the squared differences between the actual Y and the predicted Y.RSS = Σ (Y – f[Y])2(TSS – RSS) measures the amount of variability in the response that is explained by performing the regression.Properties of R2R2 always ranges between 0 to 1.R2 of 0 means that there is no correlation between the dependent and the independent variable.R2 of 1 means the dependent variable can be predicted from the independent variable without any error. An R2 between 0 and 1 indicates the extent to which the dependent variable is predictable. An R2 of 0.20 means that there is 20% of the variance in Y is predictable from X; an R2 of 0.40 means that 40% is predictable; and so on.Root Mean Square Error (RMSE)Root Mean Square Error (RMSE) is the standard deviation of the residuals (prediction errors). The formula for calculating RMSE is:Where N : Total number of observationsWhen standardized observations are used as RMSE inputs, there is a direct relationship with the correlation coefficient. For example, if the correlation coefficient is 1, the RMSE will be 0, because all of the points lie on the regression line (and therefore there are no errors).Mean Absolute Percentage Error (MAPE)There are certain limitations to the use of RMSE, so analysts prefer MAPE over RMSE which gives error in terms of percentages so that different models can be considered for the task and see how they perform. Formula for calculating MAPE can be written as:Where N : Total number of observationsFeature SelectionFeature selection is the automatic selection of attributes for your data that are most relevant to the predictive model you are working on. It seeks to reduce the number of attributes in the dataset by eliminating the features which are not required for the model construction. Feature selection does not totally eliminate an attribute which is considered for the model, rather it mutes that particular characteristic and works with the features which affects the model.Feature selection method aids your mission to create an accurate predictive model. It helps you by choosing features that will give you as good or better accuracy whilst requiring less data. Feature selection methods can be used to identify and remove unnecessary, irrelevant and redundant attributes from the data that do not contribute to the accuracy of the model or may even decrease the accuracy of the model. Having fewer attributes is desirable because it reduces the complexity of the model, and a simpler model is easier to understand, explain and to work with.Feature Selection Algorithms:Filter Method: This method involves assigning scores to individual features and ranking them. The features that have very little to almost no impact are removed from consideration while constructing the model.Wrapper Method: Wrapper method is quite similar to Filter method except the fact that it considers attributes in a group i.e. a number of attributes are taken and checked whether they are having an impact on the model and if not another combination is applied.Embedded Method: Embedded method is the best and most accurate of all the algorithms. It learns the features that affect the model while the model is being constructed and takes into consideration only those features. The most common type of embedded feature selection methods are regularization methods.Cost FunctionCost function helps to figure out the best possible plots which can be used to draw the line of best fit for the data points. As we want to reduce the error of the resulting value we change the process of finding out the actual result to a process which can reduce the error between the predicted value and the actual value.Here, J is the cost function.The above function is made in this format to calculate the error difference between the predicted values and the plotted values. We take the square of the summation of all the data points and divide it by the total number of data points. This cost function J is also called the Mean Squared Error (MSE) function. Using this MSE function we are going to predict values such that the MSE value settles at the minima, reducing the cost function.Gradient DescentGradient Descent is an optimization algorithm that helps machine learning models to find out paths to a minimum value using repeated steps. Gradient descent is used to minimize a function so that it gives the lowest output of that function. This function is called the Loss Function. The loss function shows us how much error is produced by the machine learning model compared to actual results. Our aim should be to lower the cost function as much as possible. One way of achieving a low cost function is by the process of gradient descent. Complexity of some equations makes it difficult to use, partial derivative of the cost function with respect to the considered parameter can provide optimal coefficient value. You may refer to the article on Gradient Descent for Machine Learning.Simple Linear RegressionOptimization is a big part of machine learning and almost every machine learning algorithm has an optimization technique at its core for increased efficiency. Gradient Descent is such an optimization algorithm used to find values of coefficients of a function that minimizes the cost function. Gradient Descent is best applied when the solution cannot be obtained by analytical methods (linear algebra) and must be obtained by an optimization technique.Residual Analysis: Simple linear regression models the relationship between the magnitude of one variable and that of a second—for example, as x increases, y also increases. Or as x increases, y decreases. Correlation is another way to measure how two variables are related. The models done by simple linear regression estimate or try to predict the actual result but most often they deviate from the actual result. Residual analysis is used to calculate by how much the estimated value has deviated from the actual result.Null Hypothesis and p-value: During feature selection, null hypothesis is used to find which attributes will not affect the result of the model. Hypothesis tests are used to test the validity of a claim that is made about a particular attribute of the model. This claim that’s on trial, in essence, is called the null hypothesis. A p-value helps to determine the significance of the results. p-value is a number between 0 and 1 and is interpreted in the following way:A small p-value (less than 0.05) indicates a strong evidence against the null hypothesis, so the null hypothesis is to be rejected.A large p-value (greater than 0.05) indicates weak evidence against the null hypothesis, so the null hypothesis is to be considered.p-value very close to the cut-off (equal to 0.05) is considered to be marginal (could go either way). In this case, the p-value should be provided to the readers so that they can draw their own conclusions.Ordinary Least SquareOrdinary Least Squares (OLS), also known as Ordinary least squares regression or least squared errors regression is a type of linear least squares method for estimating the unknown parameters in a linear regression model. OLS chooses the parameters for a linear function, the goal of which is to minimize the sum of the squares of the difference of the observed variables and the dependent variables i.e. it tries to attain a relationship between them. There are two types of relationships that may occur: linear and curvilinear. A linear relationship is a straight line that is drawn through the central tendency of the points; whereas a curvilinear relationship is a curved line. Association between the variables are depicted by using a scatter plot. The relationship could be positive or negative, and result variation also differs in strength.The advantage of using Ordinary Least Squares regression is that it can be easily interpreted and is highly compatible with recent computers’ built-in algorithms from linear algebra. It can be used to apply to problems with lots of independent variables which can efficiently conveyed to thousands of data points. In Linear Regression, OLS is used to estimate the unknown parameters by creating a model which will minimize the sum of the squared errors between the observed data and the predicted one.Let us simulate some data and look at how the predicted values (Yₑ) differ from the actual value (Y):import pandas as pd import numpy as np from matplotlib import pyplot as plt # Generate 'random' data np.random.seed(0) X = 2.5 * np.random.randn(100) + 1.5   # Array of 100 values with mean = 1.5, stddev = 2.5 res = 0.5 * np.random.randn(100)         # Generate 100 residual terms y = 2 + 0.3 * X + res                   # Actual values of Y # Create pandas dataframe to store our X and y values df = pd.DataFrame(     {'X': X,       'y': y} ) # Show the first five rows of our dataframe df.head()XY05.9101314.71461512.5003932.07623823.9468452.54881137.1022334.61536846.1688953.264107To estimate y using the OLS method, we need to calculate xmean and ymean, the covariance of X and y (xycov), and the variance of X (xvar) before we can determine the values for alpha and beta.# Calculate the mean of X and y xmean = np.mean(X) ymean = np.mean(y) # Calculate the terms needed for the numator and denominator of beta df['xycov'] = (df['X'] - xmean) * (df['y'] - ymean) df['xvar'] = (df['X'] - xmean)**2 # Calculate beta and alpha beta = df['xycov'].sum() / df['xvar'].sum() alpha = ymean - (beta * xmean) print(f'alpha = {alpha}') print(f'beta = {beta}')alpha = 2.0031670124623426 beta = 0.3229396867092763Now that we have an estimate for alpha and beta, we can write our model as Yₑ = 2.003 + 0.323 X, and make predictions:ypred = alpha + beta * XLet’s plot our prediction ypred against the actual values of y, to get a better visual understanding of our model.# Plot regression against actual data plt.figure(figsize=(12, 6)) plt.plot(X, ypred) # regression line plt.plot(X, y, 'ro')   # scatter plot showing actual data plt.title('Actual vs Predicted') plt.xlabel('X') plt.ylabel('y') plt.show()The blue line in the above graph is our line of best fit, Yₑ = 2.003 + 0.323 X.  If you observe the graph carefully, you will notice that there is a linear relationship between X and Y. Using this model, we can predict Y from any values of X. For example, for X = 8,Yₑ = 2.003 + 0.323 (8) = 4.587RegularizationRegularization is a type of regression that is used to decrease the coefficient estimates down to zero. This helps to eliminate the data points that don’t actually represent the true properties of the model, but have appeared by random chance. The process is done by identifying the points which have deviated from the line of best-fit by a large extent. Earlier we saw that to estimate the regression coefficients β in the least squares method, we must minimize the term Residual Sum of Squares (RSS). Let the RSS equation in this case be:The general linear regression model can be expressed using a condensed formula:Here, β=[β0 ,β1, ….. βp]The RSS value will adjust the coefficient, β based on the training data. If the resulting data deviates too much from the training data, then the estimated coefficients won’t generalize well to the future data. This is where regularization comes in and shrinks or regularizes these learned estimates towards zero.Ridge regressionRidge regression is very similar to least squares, except that the Ridge coefficients are estimated by minimizing a different quantity. In particular, the Ridge regression coefficients β are the values that minimize the following quantity:Here, λ is the tuning parameter that decides how much we want to penalize the flexibility of the model. λ controls the relative impact of the two components: RSS and the penalty term. If λ = 0, the Ridge regression will produce a result similar to least squares method. If λ → ∞, all estimated coefficients tend to zero. Ridge regression produces different estimates for different values of λ. The optimal choice of λ is crucial and should be done with cross-validation. The coefficient estimates produced by ridge regression method is also known as the L2 norm.The coefficients generated by Ordinary Least Squares method is independent of scale, which means that if each input variable is multiplied by a constant, the corresponding coefficient will be divided by the same constant, as a result of which the multiplication of the coefficient and the input variables will remain the same. The same is not true for ridge regression and we need to bring the coefficients to the same scale before we perform the process. To standardize the variables, we must subtract their means and divide it by their standard deviations.Lasso RegressionLeast Absolute Shrinkage and Selection Operator (LASSO) regression also shrinks the coefficients by adding a penalty to the sum of squares of the residuals, but the lasso penalty has a slightly different effect. The lasso penalty is the sum of the absolute values of the coefficient vector, which corresponds to its L1 norm. Hence, the lasso estimate is defined by:Similar to ridge regression, the input variables need to be standardized. The lasso penalty makes the solution nonlinear, and there is no closed-form expression for the coefficients as in ridge regression. Instead, the lasso solution is a quadratic programming problem and there are available efficient algorithms that compute the entire path of coefficients that result for different values of λ with the same computational cost as for ridge regression.The lasso penalty had the effect of gradually reducing some coefficients to zero as the regularization increases. For this reason, the lasso can be used for the continuous selection of a subset of features.Linear Regression with multiple variablesLinear regression with multiple variables is also known as "multivariate linear regression". We now introduce notation for equations where we can have any number of input variables.x(i)j=value of feature j in the ith training examplex(i)=the input (features) of the ith training examplem=the number of training examplesn=the number of featuresThe multivariable form of the hypothesis function accommodating these multiple features is as follows:hθ(x)=θ0+θ1x1+θ2x2+θ3x3+⋯+θnxnIn order to develop intuition about this function, we can think about θ0 as the basic price of a house, θ1 as the price per square meter, θ2 as the price per floor, etc. x1 will be the number of square meters in the house, x2 the number of floors, etc.Using the definition of matrix multiplication, our multivariable hypothesis function can be concisely represented as:This is a vectorization of our hypothesis function for one training example; see the lessons on vectorization to learn more.Remark: Note that for convenience reasons in this course we assume x0 (i) =1 for (i∈1,…,m). This allows us to do matrix operations with θ and x. Hence making the two vectors ‘θ’and x(i) match each other element-wise (that is, have the same number of elements: n+1).Multiple Linear RegressionHow is it different?In simple linear regression we use a single independent variable to predict the value of a dependent variable whereas in multiple linear regression two or more independent variables are used to predict the value of a dependent variable. The difference between the two is the number of independent variables. In both cases there is only a single dependent variable.MulticollinearityMulticollinearity tells us the strength of the relationship between independent variables. Multicollinearity is a state of very high intercorrelations or inter-associations among the independent variables. It is therefore a type of disturbance in the data, and if present in the data the statistical inferences made about the data may not be reliable. VIF (Variance Inflation Factor) is used to identify the Multicollinearity. If VIF value is greater than 4, we exclude that variable from our model.There are certain reasons why multicollinearity occurs:It is caused by an inaccurate use of dummy variables.It is caused by the inclusion of a variable which is computed from other variables in the data set.Multicollinearity can also result from the repetition of the same kind of variable.Generally occurs when the variables are highly correlated to each other.Multicollinearity can result in several problems. These problems are as follows:The partial regression coefficient due to multicollinearity may not be estimated precisely. The standard errors are likely to be high.Multicollinearity results in a change in the signs as well as in the magnitudes of the partial regression coefficients from one sample to another sample.Multicollinearity makes it tedious to assess the relative importance of the independent variables in explaining the variation caused by the dependent variable.Iterative ModelsModels should be tested and upgraded again and again for better performance. Multiple iterations allows the model to learn from its previous result and take that into consideration while performing the task again.Making predictions with Linear RegressionLinear Regression can be used to predict the value of an unknown variable using a known variable by the help of a straight line (also called the regression line). The prediction can only be made if it is found that there is a significant correlation between the known and the unknown variable through both a correlation coefficient and a scatterplot.The general procedure for using regression to make good predictions is the following:Research the subject-area so that the model can be built based on the results produced by similar models. This research helps with the subsequent steps.Collect data for appropriate variables which have some correlation with the model.Specify and assess the regression model.Run repeated tests so that the model has more data to work with.To test if the model is good enough observe whether:The scatter plot forms a linear pattern.The correlation coefficient r, has a value above 0.5 or below -0.5. A positive value indicates a positive relationship and a negative value represents a negative relationship.If the correlation coefficient shows a strong relationship between variables but the scatter plot is not linear, the results can be misleading. Examples on how to use linear regression have been shown earlier.Data preparation for Linear RegressionStep 1: Linear AssumptionThe first step for data preparation is checking for the variables which have some sort of linear correlation between the dependent and the independent variables.Step 2: Remove NoiseIt is the process of reducing the number of attributes in the dataset by eliminating the features which have very little to no requirement for the construction of the model.Step 3: Remove CollinearityCollinearity tells us the strength of the relationship between independent variables. If two or more variables are highly collinear, it would not make sense to keep both the variables while evaluating the model and hence we can keep one of them.Step 4: Gaussian DistributionsThe linear regression model will produce more reliable results if the input and output variables have a Gaussian distribution. The Gaussian theorem states that  states that a sample mean from an infinite population is approximately normal, or Gaussian, with mean the same as the underlying population, and variance equal to the population variance divided by the sample size. The approximation improves as the sample size gets large.Step 5: Rescale InputsLinear regression model will produce more reliable predictions if the input variables are rescaled using standardization or normalization.Linear Regression with statsmodelsWe have already discussed OLS method, now we will move on and see how to use the OLS method in the statsmodels library. For this we will be using the popular advertising dataset. Here, we will only be looking at the TV variable and explore whether spending on TV advertising can predict the number of sales for the product. Let’s start by importing this csv file as a pandas dataframe using read_csv():# Import and display first five rows of advertising dataset advert = pd.read_csv('advertising.csv') advert.head()TVRadioNewspaperSales0230.137.869.222.1144.539.345.110.4217.245.969.312.03151.541.358.516.54180.810.858.417.9Now we will use statsmodels’ OLS function to initialize simple linear regression model. It will take the formula y ~ X, where X is the predictor variable (TV advertising costs) and y is the output variable (Sales). Then, we will fit the model by calling the OLS object’s fit() method.import statsmodels.formula.api as smf # Initialise and fit linear regression model using `statsmodels` model = smf.ols('Sales ~ TV', data=advert) model = model.fit()Once we have fit the simple regression model, we can predict the values of sales based on the equation we just derived using the .predict method and also visualise our regression model by plotting sales_pred against the TV advertising costs to find the line of best fit.# Predict values sales_pred = model.predict() # Plot regression against actual data plt.figure(figsize=(12, 6)) plt.plot(advert['TV'], advert['Sales'], 'o')       # scatter plot showing actual data plt.plot(advert['TV'], sales_pred, 'r', linewidth=2)   # regression line plt.xlabel('TV Advertising Costs') plt.ylabel('Sales') plt.title('TV vs Sales') plt.show()In the above graph, if you notice you will see that there is a positive linear relationship between TV advertising costs and Sales. You may also summarize by saying that spending more on TV advertising predicts a higher number of sales.Linear Regression with scikit-learnLet us learn to implement linear regression models using sklearn. For this model as well, we will continue to use the advertising dataset but now we will use two predictor variables to create a multiple linear regression model. Yₑ = α + β₁X₁ + β₂X₂ + … + βₚXₚ, where p is the number of predictors.In our example, we will be predicting Sales using the variables TV and Radio i.e. our model can be written as:Sales = α + β₁*TV + β₂*Radiofrom sklearn.linear_model import LinearRegression # Build linear regression model using TV and Radio as predictors # Split data into predictors X and output Y predictors = ['TV', 'Radio'] X = advert[predictors] y = advert['Sales'] # Initialise and fit model lm = LinearRegression() model = lm.fit(X, y) print(f'alpha = {model.intercept_}') print(f'betas = {model.coef_}')alpha = 4.630879464097768 betas = [0.05444896 0.10717457]model.predict(X)Now that we have fit a multiple linear regression model to our data, we can predict sales from any combination of TV and Radio advertising costs. For example, you want to know how many sales we would make if we invested $600 in TV advertising and $300 in Radio advertising. You can simply find it out by:new_X = [[600, 300]] print(model.predict(new_X))[69.4526273]We get the output as 69.45 which means if we invest $600 on TV and $300 on Radio advertising, we can expect to sell 69 units approximately.SummaryLet us sum up what we have covered in this article so far —How to understand a regression problemWhat is linear regression and how it worksOrdinary Least Square method and RegularizationImplementing Linear Regression in Python using statsmodel and sklearn libraryWe have discussed about a couple of ways to implement linear regression and build efficient models for certain business problems. If you are inspired by the opportunities provided by machine learning, enrol in our  Data Science and Machine Learning Courses for more lucrative career options in this landscape.
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What is Linear Regression in Machine Learning

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What Is Data Science(with Examples), It's Lifecycle and Who exactly is a Data Scientist

Oh yes, Science is everywhere. A while ago, when children embarked on the journey of learning everyday science in school, the statement that always had a mention was “Science is everywhere”. The situation is more or less the same even in present times. Science has now added a few feathers to its cap. Yes, the general masses sing the mantra “Data Science” is everywhere. What does it mean when I say Data Science is everywhere? Let us take a look at the Science of Data. What are those aspects that make this Science unique from everyday Science?The Big Data Age as you may call it has in it Data as the object of study.Data Science for a person who has set up a firm could be a money spinnerData Science for an architect working at an IT consulting company could be a bread earnerData Science could be the knack behind the answers that come out from the juggler’s hatData Science could be a machine imported from the future, which deals with the Math and Statistics involved in your lifeData science is a platter full of data inference, algorithm development, and technology. This helps the users find recipes to solve analytically complex problems.With data as the core, we have raw information that streams in and is stored in enterprise data warehouses acting as the condiments to your complex problems. To extract the best from the data generated, Data Science calls upon Data Mining. At the end of the tunnel, Data Science is about unleashing different ways to use data and generate value for various organizations.Let us dig deeper into the tunnel and see how various domains make use of Data Science.Example 1Think of a day without Data Science, Google would not have generated results the way it does today.Example 2Suppose you manage an eatery that churns out the best for different taste buds. To model a product in the pipeline, you are keen on knowing what the requirements of your customers are. Now, you know they like more cheese on the pizza than jalapeno toppings. That is the existing data that you have along with their browsing history, purchase history, age and income. Now, add more variety to this existing data. With the vast amount of data that is generated, your strategies to bank upon the customers’ requirements can be more effective. One customer will recommend your product to another outside the circle; this will further bring more business to the organization.Consider this image to understand how an analysis of the customers’ requirements helps:Example 3Data Science plays its role in predictive analytics too.I have an organization that is into building devices that will send a trigger if a natural calamity is soon to occur. Data from ships, aircraft, and satellites can be accumulated and analyzed to build models that will not only help with weather forecasting but also predict the occurrence of natural calamities. The model device that I build will send triggers and save lives too.Consider the image shown below to understand how predictive analytics works:Example 4A lot many of us who are active on social media would have come across this situation while posting images that show you indulging in all fun and frolic with your friends. You might miss tagging your friends in the images you post but the tag suggestion feature available on most platforms will remind you of the tagging that is pending.The automatic tag suggestion feature uses the face recognition algorithm.Lifecycle of Data ScienceCapsulizing the main phases of the Data Science Lifecycle will help us understand how the Data Science process works. The various phases in the Data Science Lifecycle are:DiscoveryData PreparationModel PlanningModel BuildingOperationalizingCommunicating ResultsPhase 1Discovery marks the first phase of the lifecycle. When you set sail with your new endeavor,it is important to catch hold of the various requirements and priorities. The ideation involved in this phase needs to have all the specifications along with an outline of the required budget. You need to have an inquisitive mind to make the assessments – in terms of resources, if you have the required manpower, technology, infrastructure and above all time to support your project. In this phase, you need to have a business problem laid out and build an initial hypotheses (IH) to test your plan. Phase 2Data preparation is done in this phase. An analytical sandbox is used in this to perform analytics for the entire duration of the project. While you explore, preprocess and condition data, modeling follows suit. To get the data into the sandbox, you will perform ETLT (extract, transform, load and transform).We make use of R for data cleaning, transformation, and visualization and further spot the outliers and establish a relationship between the variables. Once the data is prepared after cleaning, you can play your cards with exploratory analytics.Phase 3In this phase of Model planning, you determine the methods and techniques to pick on the relationships between variables. These relationships set the base for the algorithms that will be implemented in the next phase.  Exploratory Data Analytics (EDA) is applied in this phase using various statistical formulas and visualization tools.Subsequently, we will look into the various models that are required to work out with the Data Science process.RR is the most commonly used tool. The tool comes with a complete set of modeling capabilities. This proves a good environment for building interpretive models.SQL Analysis Services SQL Analysis services has the ability to perform in-database analytics using basic predictive models and common data mining functions.SAS/ACCESS  SAS/ACCESS helps you access data from Hadoop. This can be used for creating repeatable and reusable model flow diagrams.You have now got an overview of the nature of your data and have zeroed in on the algorithms to be used. In the next stage, the algorithm is applied to further build up a model.Phase 4This is the Model building phase as you may call it. Here, you will develop datasets for training and testing purposes. You need to understand whether your existing tools will suffice for running the models that you build or if a more robust environment (like fast and parallel processing) is required. The various tools for model building are SAS Enterprise Miner, WEKA, SPCS Modeler, Matlab, Alpine Miner and Statistica.Phase 5In the Operationalize phase, you deliver final reports, briefings, code and technical documents. Moreover, a pilot project may also be implemented in a real-time production environment on a small scale. This helps users get a clear picture of the performance and other related constraints before full deployment.Phase 6The Communicate results phase is the conclusion. Here, we evaluate if you have been able to meet your goal the way you had planned in the initial phase. It is in this phase that the key findings pop their heads out. You communicate to the stakeholders in this phase. This phase brings you the result of your project whether it is a success or a failure.Why Do We Need Data Science?Data Science to be precise is an amalgamation of Infrastructure, Software, Statistics and the various data sources.To really understand big data, it would help us if we bridge back to the historical background. Gartner’s definition circa 2001, which is still the go-to definition says,Big data is data that contains greater variety arriving in increasing volumes and with ever-higher velocity. This is known as the three Vs.When we break the definition into simple terms, all that it means is, big data is humongous. This involves the multiplication of complex data sets with the addition of new data sources. When the data sets are in such high volumes, our traditional data processing software fails to manage them. It is just like how you cannot expect your humble typewriter to do the job of a computer. You cannot expect a typewriter to even do the ctrl c + ctrl v job for you. The amount of data that comes with the solutions to all your business problems is massive. To help you with the processing of this data, you have Data Science playing the key role.The concept of big data itself may sound relatively new; however, the origins of large data sets can be traced back to the 1960s and the '70s. This is when the world of data was just getting started. The world witnessed the set up of the first data centers and the development of the relational database.Around 2005, Facebook, YouTube, and other online services started gaining immense popularity. The more people indulged in the use of these platforms, the more data they generated. The processing of this data involved a lot of Data Science. The masses had to store the amassed data and analyse it at a later point. As a platform that answers to the storage and analysis of the amassed data, Hadoop was developed. Hadoop is an open-source framework that helps in the storage and analysis of big data sets. And as we say, the rest will follow suit; we had NoSQL gaining popularity during this time.With the advent of big data, the need for its storage also grew. The storage of data became a major issue for enterprise industries until 2010. We have had Hadoop, Spark and other frameworks mitigating the challenge to a very large extent. Though the volume of big data is skyrocketing, the focus remains on the processing of the data, all thanks to these efficient frameworks. And, Data Science once again hogs the limelight.Can we say it is only the users leading to huge amounts of data? No, we cannot. It is not only humans generating the data but also the work they indulge in.Delving into the iota of the Internet of Things (IoT) will get us some clarity on the question that we just raised. As we have more objects and devices connected to the Internet, data gathers not just by use but also by the pattern of your usage and the performance of the various products.The Three Vs of Big DataData Science helps in the extraction of knowledge from the accumulated data. While big data has come far with the accumulation of users’ data, its usefulness is only just beginning.Following are the Three Properties that define Big Data:VolumeVelocityVarietyVolumeThe amount of data is a crucial factor here. Big data stands as a pillar when you have to process a multitude of low-density, unstructured data. The data may contain unknown value – such as clickstreams on a webpage or a mobile app and Twitter data feeds. The values of the data may differ from user to user. For some, the value might be in tens of terabytes of data. For others, the value might be in hundreds of petabytes.Consider the different social media platforms – Facebook records 2 billion users, YouTube has 1 billion users, 350 million users for Twitter and a whopping 700 million users on Instagram. There is exchange of billions of images, posts and tweets on these platforms. Imagine the amuck storage of data the users contribute too. Mind Boggling, is it not? This insanely large amount of data is generated every minute and every hour.VelocityThe fast rate at which the data is received and acted upon is the Velocity. Usually, the data is written to the disk. When there is data with highest velocity, it streams directly into the memory. With the advancement in technology, we now have more numbers of Internet-connected devices across industries. The velocity of the data generated through these devices that act real time or near real time may call for real-time evaluation and action.Sticking to our social media example, Facebook accounts for 900 million photo uploads, Twitter handles 500 million tweets, Google is to go to solution for 3.5 billion searches, YouTube calls for 0.4 millions hours of video uploads; all this on a daily basis. The bundled amount of data is stifling.VarietyThe data generated by the users comes in different types. The different types form different varieties of data. Dating back, we had traditional data types that were structured and organized in a relational database.Texts, tweets, videos, photos uploaded form the different varieties of structured data uploaded on the Internet.Voicemails, emails, ECG reading, audio recordings and a lot more form the different varieties of unstructured data that we find on the Internet.Who is a Data Scientist? A curious brain and an impressive training is all that you need to become a Data Scientist. Not as easy as it may sound.Deep thinking, deep learning with intense intellectual curiosity is a common trait found in data scientists. The more you ask questions, the more discoveries you come up with, the more augmented your learning experience is, the more it gets easier for you to tread on the path of Data Science.A factor that differentiates a data scientist from a normal bread earner is that they are more obsessed with creativity and ingenuity. A normal bread earner will go seeking money whereas, the motivator for a data scientist is the ability to solve analytical problems with a pinch of curiosity and creativity. Data scientists are always on a treasure hunt – hunting for the best from the trove.If you think, you need a degree in Sciences or you need to be a PhD in Math to become a legitimate data scientist, mind you, you are carrying a misconception. A natural propensity in these areas will definitely add to your profile but you can be an expert data scientist without a degree in these areas too. Data Science becomes a cinch with heaps of knowledge in programming and business acumen.Data Science is a discipline gaining colossal prominence of late. Educational institutions are yet to come up with comprehensive Data Science degree programs. A data scientist can never claim to have undergone all the required schooling. Learning the rights skills, guided by self-determination is a never-ending process for a data scientist.As Data Science is multidisciplinary, many people find it confusing to differentiate between Data Scientist and Data Analyst.Data Analytics is one of the components of Data Science. Analytics help in understanding the data structure of an organization. The achieved output is further used to solve problems and ring in business insights.The Basic Differences between a Data Scientist and a Data AnalystScientists and Analysts are not exactly synonymous. The roles are not mutually exclusive either. The roles of Data Scientists and Data Analysts differ a lot. Let us take a look at some of the basic differences:CriteriaData ScientistData AnalystGoalInquisitive nature and a strong business acumen helps Data Scientists to arrive at solutionsThey perform data analysis and sourcingTasksData Scientists need to be adept at data insight mining, preparation, and analysis to extract informationData Analysts gather, arrange, process and model both structured and unstructured dataSubstantive expertiseRequiredNot RequiredNon-technical skillsRequiredNot RequiredWhat Skills Are Required To Become a Data Scientist?Data scientists blend with the best skills. The fundamental skills required to become a Data Scientist are as follows:Proficiency in MathematicsTechnology knowhow and the knack to hackBusiness AcumenProficiency in MathematicsA Data Scientist needs to be equipped with a quantitative lens. You can be a Data Scientist if you have the ability to view the data quantitatively.Before a data product is finally built, it calls for a tremendous amount of data insight mining. There are portions of data that include textures, dimensions and correlations. To be able to find solutions to come with an end product, a mathematical perspective always helps.If you have that knack for Math, finding solutions utilizing data becomes a cakewalk laden with heuristics and quantitative techniques. The path to finding solutions to major business problems is a tedious one. It involves the building of analytical models. Data Scientists need to identify the underlying nuts and bolts to successfully build models.Data Science carries with it a misconception that it is all about statistics. Statistics is crucial; however, only the Math type is more accountable. Statistics has two offshoots – the classical and the Bayesian. When people talk about stats, they are usually referring to classical stats. Data Scientists need to refer both types to arrive at solutions. Moreover, there is a mix of inferential techniques and machine learning algorithms; this mix leans on the knowledge of linear algebra. There are popular methods in Data Science; finding a solution using these methods calls upon matrix math which has got very less to do with classical stats.Technology knowhow and the knack to hackOn a lighter note, let us put a disclaimer… you are not being asked to learn hacking to come crashing on computers. As a hacker, you need to be gelled with the amalgam of creativity and ingenuity. You are expected to use the right technical skills to build models and thereby find solutions to complex analytical problems.Why does the world of Data Science vouch on your hacking ability? The answer finds its element in the use of technology by Data Scientists. Mindset, training and the right technology when put together can squeeze out the best from mammoth data sets. Solving complex algorithms requires more sophisticated tools than just Excel. Data scientists need to have the nitty-gritty ability to code. They should be able to prototype quick solutions, as well as integrate with complex data systems. SQL, Python, R, and SAS are the core languages associated with Data Science. A knowhow of Java, Scala, Julia, and other languages also helps. However, the knowledge of language fundamentals does not suffice the quest to extract the best from enormous data sets. A hacker needs to be creative to sail through technical waters and make the codes reach the shore.Business AcumenA strong business acumen is a must-have in the portfolio of any Data Scientist. You need to make tactical moves and fetch that from the data, which no one else can. To be able to translate your observation and make it a shared knowledge calls for a lot of responsibility that can face no fallacy.With the right business acumen, a Data Scientist finds it easy to present a story or the narration of a problem or a solution.To be able to put your ideas and the solutions you arrive at across the table, you need to have business acumen along with the prowess for tech and algorithms.Data, Math, and tech will not help always. You need to have a strong business influence that can further be influenced by a strong business acumen.Companies Using Data ScienceTo address the issues associated with the management of complex and expanding work environments, IT organizations make use of data to identify new value sources. The identification helps them exploit future opportunities and to further expand their operations. What makes the difference here is the knowledge you extract from the repository of data. The biggest and the best companies use analytics to efficiently come up with the best business models.Following are a few top companies that use Data Science to expand their services and increase their productivity.GoogleAmazonProcter & GambleNetflixGoogle Google has always topped the list on a hiring spree for top-notch data scientists. A force of data scientists, artificial intelligence and machine learning by far drives Google. Moreover, when you are here, you get the best when you give the best of your data expertise.AmazonAmazon, the global e-commerce and cloud computing giant hire data scientists on a big scale. To bank upon the customers’ mindsets, enhance the geographical outreach of both the cloud domain and e-commerce domain among other business-driven goals, they make use of Data Science. Data Scientists play a crucial role in steering Data Science.Procter & Gamble and NetflixBig Data is a major component of Data Science.It has answers to a range of business problems – from customer experience to analytics.Netflix and Procter & Gamble join the race of product development by using big data to anticipate customer demand. They make use of predictive analytics, an offshoot of Data Science to build models for services in their pipeline. This modelling is an attribute that contributes to their commercial success. The significant addition to the commercial success of P&G is that it uses data and analytics from test markets, social media, and early store rollouts. Following this strategy, it further plans, produces, and launches the final products. And, the finale often garners an overwhelming response for them.The Final Component of the Big Data StoryWhen speed multiplied with storage capabilities, thus evolved the final component of the Big Data story – the generation and collection of the data. If we still had massive room-sized calculators working as computers, we may not have come across the humongous amount of data that we see today. With the advancement in technology, we called upon ubiquitous devices. With the increase in the number of devices, we have more data being generated. We are generating data at our own pace from our own space owing to the devices that we make use of from our comfort zones. Here I tweet, there you post, while a video is being uploaded on some platform by someone from some corner of the room you are seated in.The more you inform people about what you are doing in your life, the more data you end up writing. I am happy and I share a quote on Facebook expressing my feelings; I am contributing to more data. This is how enormous amount of data is generated. The Internet-connected devices that we use support in writing data. Anything that you engage with in this digital world, the websites you browse, the apps you open on your cell phone, all the data pertaining to these can be logged in a database miles away from you.Writing data and storing it is not an arduous task anymore. At times, companies just push the value of the data to the backburner. At some point of time, this data will be fetched and cooked when they see the need for it.There are different ways to cash upon the billions of data points. Data Science puts the data into categories to get a clear picture. On a Final NoteIf you are an organization looking out to expand your horizons, being data-driven will take you miles. The application of an amalgam of Infrastructure, Software and Statistics, and the various data sources is the secret formula to successfully arrive at key business solutions. The future belongs to Data Science. Today, it is data that we see all around us. This new age sounds the bugle for more opportunities in the field of Data Science. Very soon, the world will need around one million Data Scientists.If you are keen on donning the hat of a Data Scientist, be your own architect when it comes to solving analytical problems. You need to be a highly motivated problem solver to overcome the toughest analytical challenges.
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What Is Data Science(with Examples), It's Lif...

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