Like numerical data, categorical data can also be organized and analysed. In this section, we will introduce tables and other basic tools for categorical data that are used throughout this course. The email50 data set represents a sample from a larger email data set called email. This larger data set contains information on 3,921 emails. In this section we will examine whether the presence of numbers, small or large, in an email provides any useful value in classifying email as spam or not spam.