Machine Learning       15CS73
MODULE 2 – DECISION TREE LEARNING
1. What is decision tree and decision tree learning?
2. Explain representation of decision tree with example.
3. What are appropriate problems for Decision tree learning?
4. Explain the concepts of Entropy and Information gain.
5. Describe the ID3 algorithm for decision tree learning with example
6. Give Decision trees to represent the Boolean Functions:
        a) A && ~ B
        b) A V [B && C]
        c) A XOR B
        d) [A&&B] V [C&&D]
7. Give Decision trees for the following set of training examples
          Day    Outlook Temperature Humidity Wind PlayTennis
          D1      Sunny     Hot        High   Weak     No
          D2      Sunny     Hot        High   Strong   No
          D3     Overcast   Hot        High   Weak    Yes
          D4       Rain     Mild       High   Weak    Yes
          D5       Rain     Cool      Normal  Weak    Yes
          D6       Rain     Cool      Normal Strong    No
          D7     Overcast   Cool      Normal Strong   Yes
          D8      Sunny     Mild       High   Weak     No
          D9      Sunny     Cool      Normal  Weak    Yes
          D10      Rain     Mild      Normal  Weak    Yes
          D11     Sunny     Mild      Normal Strong   Yes
          D12    Overcast   Mild       High   Strong  Yes
          D13    Overcast   Hot       Normal  Weak    Yes
          D14      Rain     Mild       High   Strong   No
8. Consider the following set of training examples.
   a) What is the entropy of this collection of training example with respect to the target
        function classification?
   b) What is the information gain of a2 relative to these training examples?
    1      Deepak D, Asst. Prof., Dept. of CS&E, Canara Engineering College, Mangaluru
                                                            Machine Learning       15CS73
                        Instance Classification      a1    a2
                            1          +             T     T
                            2          +             T     T
                            3          -             T     F
                            4          +             F     F
                            5          -             F     T
                            6          -             F     T
9. Identify the entropy, information gain and draw the decision trees for the following set
   of training examples
                     Car       Travel cost       Income     Transportation
         Gender
                   ownership                      Level        (Class)
          Male        0          Cheap            Low            Bus
          Male        1          Cheap           Medium          Bus
         Female       1          Cheap           Medium         Train
         Female       0          Cheap            Low            Bus
          Male        1          Cheap           Medium          Bus
          Male        0         Standard         Medium         Train
         Female       1         Standard         Medium         Train
         Female       1        Expensive          High           Car
          Male        2        Expensive         Medium          Car
         Female       2        Expensive          High           Car
10. Discuss Hypothesis Space Search in Decision tree Learning.
11. Discuss Inductive Bias in Decision Tree Learning.
12. What are Restriction Biases and Preference Biases and differentiate between them.
13. Write a note on Occam’s razor and minimum description principal.
14. What are issues in learning decision trees
    2     Deepak D, Asst. Prof., Dept. of CS&E, Canara Engineering College, Mangaluru