In the previous chapter, we learned the basics of machine learning. In this chapter, we will build models that predict categories. This class of machine learning problems is known as classification tasks. Classification models are the ones that are the most useful in practice, and in this chapter we will talk about some of the most popular and foundational classification models.

We begin the chapter by providing an overview of the classification tasks and some of their applications. Then we bring back our credit card default dataset and start preparing it for modeling. After that, we introduce one of the most popular models for classification—logistic regression, which is similar in spirit to the multiple regression models we discussed in the previous chapter. The next model we present is classification trees. We present this...