## Comparing Classification and Regression - Intro to Machine Learning

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Here's a quick comparison between classification and regression.
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We'll go into more detail in everything that I write here.
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But I want to give you a quick overview just so
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you know what to look out for in this lesson.
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So the first thing I'll mention is the output type of the algorithm.
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As you know, for supervised classification,
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this is going to be discrete in the form of class labels.
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For regression this is continuous.
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Which basically means that you'll be predicting a number using a regression.
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The next question, a very important question is what are you actually trying to
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find when you perform a classification or a regression?
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In the case of classification this is usually a decision boundary.
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And then depending on where a point follows relative to
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that decision boundary you can assign it a class label.
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With a regression what we're trying to find is something we usually call
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a best fit line.
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Which is a line that fits the data rather than a boundary that describes it.
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This will make a lot more sense in the next couple of videos.
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The last thing I'll mention is how to evaluate.
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When we were doing supervised classification we usually use the accuracy,
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which is whether it got the class labels correct or not on your test set.
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And for regression we'll talk about a couple different evaluation metrics.
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One of which is called the sum of a squared error.
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Another one is called r squared.
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I'll tell you a lot more about both of these in the middle part of the lesson.
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The main point I want you to take away from this is that,
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while regression isn't exactly the same as supervised classification.
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A lot of the things you already know about supervised classification have direct
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analogs in regression.
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So you should think of regression as a different type of supervised learning.
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Not as a completely new topic that you now have to learn from scratch.
Title:
Comparing Classification and Regression - Intro to Machine Learning
Description:

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Video Language:
English
Team:
Udacity
Project:
ud120 - Intro to Machine Learning
Duration:
01:37
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