Classification algorithms are a type of machine learning algorithm that involve determining the class (category or type) of a given item. For instance, we could try to determine the genre of a movie based on some features. In this case, the genre is the class to be predicted. In the next chapter, Chapter 10, Predictive Analytics and Machine Learning, we will continue with an overview of machine learning. In the meantime, we will discuss a popular algorithm called Naive Bayes classification, which is frequently used to analyze text documents.

Naive Bayes classification is a probabilistic algorithm based on the Bayes theorem from probability theory and statistics. The Bayes theorem formulates how to discount the probability of an event based on new evidence. For example, imagine that we have a bag with pieces of chocolate and other items we can't see. We will call the probability of drawing a piece of dark chocolate P(D). We will denote the probability of drawing...