we used logistic regression to predict the probability of default using income

In Chapter 4, we used logistic regression to predict the probability of default using income and balance on the Default data set. We will now estimate the test error of this logistic regression model using the validation set approach. Do not forget to set a random seed before beginning your analysis.
(a) (10 points) Fit a logistic regression model that uses income and balance to predict default. (b) (10 points total) Using the validation set approach, estimate the test error of this model. In order to do this, you must perform the following steps: i. (2.5 points) Split the sample set into a training set and a validation set. ii. (2.5 points) Fit a multiple logistic regression model using only the training observations.