The following table lists a dataset containing the details of six patients. Each patient is described in terms of three binary descriptive features (Obese, Smoker, and Drinks Alcohol) and a target feature (Cancer Risk).
ID Obese Smoker Drinks Alcohol Cancer Risk
1 true false true low
2 true true true high
3 true false true low
4 false true true high
5 false true false low
6 false true true high
a. Which of the descriptive features will the ID3 decision tree induction algorithm choose as the feature for the root node of the decision tree?
b. When designing a dataset, it is generally a bad idea if all of the descriptive features are indicators of the target feature taking a particular value. For example, a potential criticism of the design of the dataset in this question is that all the descriptive features are indicators of the Cancer Risk Target feature taking the same level, high. Can you think of any descriptive features that could be added to the dataset that are indicators of the low target level?