[ML] {ud120} Lesson 4: Decision Trees

Linearly Separable Data

 

 

 

 

 

 Multiple Linear Questions

 

 

 

 

 

 

 

Constructing a Decision Tree First Split 

 

 

 

 

 Coding A Decision Tree

 

 

 

 

 

 

 

 

 

 Decision Tree Parameters

 

 

 

 

 Data Impurity and Entropy

 

 

 

 

 Formula of Entropy

 

 

There is an error in the formula in the entropy written on this slide. There should be a negative (-) sign preceding the sum:

Entropy = - \sum_i (p_i) \log_2 (p_i)−∑i​(pi​)log2​(pi​)

 

 

 

 

 

IG = 1

 

 

 

 Tuning Criterion Parameter

 

gini is another measurement of purity

 

 

 

Decision Tree Mini-Project

 

In this project, we will again try to identify the authors in a body of emails, this time using a decision tree. The starter code is in decision_tree/dt_author_id.py.

Get the data for this mini project from here.

Once again, you'll do the mini-project on your own computer and enter your answers in the web browser. You can find the instructions for the decision tree mini-project here.