1. Decision Trees: Another Example
Play Tennis?
Training Set:
Weak
Rain Mild High Weak No
Rain Mild High Weak No

2. Decision Trees: Another Example
Play Tennis?
Sunny
Training Set:
Weak
Rain Mild High Weak No
Rain Mild High Weak No

3. Decision Trees: Another Example
Play Tennis?
Sunny
Hot
Training Set:
Weak
Rain Mild High Weak No
Rain Mild High Weak No

4. Decision Trees: Another Example
Play Tennis?
Sunny
Mild
Training Set:
Weak
Rain Mild High Weak No
Rain Mild High Weak No

5. Decision Trees: Another Example
Play Tennis?
Sunny
Mild
Humidity High – No
Humidity Normal – Yes
Training Set:
Weak
Rain Mild High Weak No
Rain Mild High Weak No

6. Decision Trees: Another Example
Play Tennis?
Sunny
Cool
Training Set:
Weak
Rain Mild High Weak No
Rain Mild High Weak No

7. Decision Trees: Another Example
Play Tennis?
Overcast
Training Set:
Weak
Rain Mild High Weak No
Rain Mild High Weak No

8. Decision Trees: Another Example
Play Tennis?
Rain
Training Set:
Weak
Rain Mild High Weak No
Rain Mild High Weak No

9. Decision Trees: Another Example
Play Tennis?
Rain
Hot – No examples!
Training Set:
Weak
Rain Mild High Weak No
Rain Mild High Weak No

10. Decision Trees: Another Example
Play Tennis?
Rain
Mild
Training Set:
Weak
Rain Mild High Weak No
Rain Mild High Weak No

11. Decision Trees: Another Example
Play Tennis?
Rain
Mild
High Humidity
Training Set:
Weak
Rain Mild High Weak No
Rain Mild High Weak No

12. Decision Trees: Another Example
Play Tennis?
Rain
Mild
High Humidity
Weak Wind
Training Set:
Weak
Rain Mild High Weak No
Rain Mild High Weak No

13. Wait for a Table?

14. Choosing the Best Feature
Compare Type and Patrons
Which one seems better?
True examples
False examples
False
True

15. Choosing the Best Feature
Compare Type and Patrons
Which one seems better?
At each node select the feature that divides the examples into sets which are almost all positive or all negative.
Yes examples
No examples