Exercise 10        Name __________________        Score __/14

1. (2) Draw a decision tree for the following even parity training set.

   N	X3	X2	X1	X0	Target
   1	F	F	F	F	F
   2	F	F	F	T	T
   3	F	F	T	F	T
   4	F	F	T	T	F
   5	F	T	F	F	T
   6	T	F	F	F	T
   7	T	F	T	F	F
   8	T	F	T	T	T
   9	T	T	F	T	T
   10	T	T	T	F	T
   11	T	T	T	T	F

2. (2) Calculate the information content of Target.
 

3. (2) Calculate the gain of X1.

4. (2) Calculate the information content of Target after selecting the F branch of X1.

5. (2) Calculate the gain of X3 after selecting the F branch of X1.

6. (3) Verify your answers in 3-5 using Figure 18.5 of text. Draw the decision tree produced by ID3.

7. (1) Is the prediction for X3=F, X2=T, X1=T, X0=T correct?

         X0, though the highest, had a low information gain (Question 3), what does that say about the predictive power of our decision tree?