A marketing manager wants to predict customers with risk of churning (switching their service contracts to another company) based on the number of calls the customer makes to the company call center and the number of visits the customer makes to the local service center. Data from a random sample of 30 customers are organized and stored in Churn .

a. Using all the data as the training sample, develop a classification tree model to predict the probability of churning, based on the number of calls the customer makes to the company call center and the number of visits the customer makes to the local service center.

b. What conclusions can you reach about the probability of churning?