How to Prune Regression Trees, Clearly Explained!!!

Pruning Regression Trees is one the most important ways we can prevent them from overfitting the Training Data. This video walks you through Cost Complexity Pruning, aka Weakest Link Pruning, step-by-step so that you can learn how it works and see it in action.
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0:00 Awesome song and introduction
0:59 Motivation for pruning a tree
3:58 Calculating the sum of squared residuals for pruned trees
7:50 Comparing pruned trees with alpha.
11:17 Step 1: Use all of the data to build trees with different alphas
13:05 Step 2: Use cross validation to compare alphas
15:02 Step 3: Select the alpha that, on average, gives the best results
15:27 Step 4: Select the original tree that corresponds to that alpha

#statquest #regression #tree

[statquest]

NOTE: To apply this method to a classification, replace SSR with Gini Impurity (or Information Gain or Entropy or whatever metric you are using).

[Nihit-nn]

Josh: you have truly cracked how to use technology(slides/basic animation) to change the way we are teaching for decades. I wish all universities take a note from you and revise the way they are teaching

[gayathrigirishnair]

This is the best explanation of regression trees that I could find online. Professors are always too mathematical and programmers are too practical. You're explanation is juusssst right. Thanks a bunch for this!

[andyjiang]

The channel with the lowest Gini score of likes vs. dislikes

[jiaxuzhang]

Absolutely brillian videos!!! I watched everything from the 1st one to this one in the list and understood so many things that I never understood in schools. I love your videos so much!

[pratyanshvaibhav]

sir i am learning ML from your videos and everyday i am forced to comment expressing the beauty with which the concept is explained..and the best part is you still clear our doubts even after 3 years..for those who don't know sir has also written a book which is too good

[gunupurugirija]

lol, that intro one who watches friends and Stat Quest would get it!! love your content its the best machine learning tutorials available

[aop]

This is awesome. I remember I was a bit confused when I was reading tree based methods in An Introduction to Statistical Learning. This really helps me understand it much easier when I can visualize it other than read some formulas. Thank you!

[alecvan]

Re watching after practising I can even further appreciate the quality of your explanations, thanks Josh :)

[eramitjangra]

I searched lot of thing for my project on ML to start from scratch.
Then i landed here
You nailed it. 🔥🔥🙏
Now i am on edge of completing my project
thank a lot

[munawersheikh]

I love the way you say "BAMM"!!! Gives great relief during the video :) I want to say your style of teaching is great. The way you are explaining is making very easy for us to understand. In my opinion I can say "A difficult subject with easy to understand using your video lectures!" Thank you very much.

[triplefruition]

Oh my Buddha!
I'm falling in love with funny of your voice when you're explaining.
Before I met your channel, my head is spinning round and round.
I don't know what to do with my learning, but you came in and took me by big surprise.
You made the abstract concept to be simple!
Thank

[LQNam]

Thanks, Josh Starmer. The way of using train + test data to find a list of alpha, then use K-fold CV on train data to find out the optimal alpha leads to the data leakage.

[auzaluis]

I don't know why I spend a lot of time googling if I always end up watching statquest haahahha

[dhananjaykansal]

Ahhh Phobeee from Friends aka Smelly Cat. Haha good one Josh.

[ldk]

What a beautiful content!
I'm not an English speaker, but His video is more helpful than the Korean lecture provided by the college I attending.

[preranadas]

Best video on pruning and tree selection till

[tymothylim]

Thank you very much for this video! I really enjoyed the full step-by-step process of building the various trees using different alpha values and the use of cross validation to select the best alpha!

[mujeebrahman]

The good thing about his videos is you just have to watch any video once and the concept will not leave you for a long time.

[enlighteninginformation]

This video really helped me to clearly understand the concept. Thank you for this good work