Getting started with two types of data – numerical and categorical
At first glance, the features in the preceding dataset are categorical, for example, male or female, one of four age groups, one of the predefined site categories, or whether the user is interested in sports. Such data is different from the numerical feature data we have worked with until now.
Categorical (also called qualitative) features represent characteristics, distinct groups, and a countable number of options. Categorical features may or may not have a logical order. For example, household income from low to medium to high is an ordinal feature, while the category of an ad is not ordinal.
Numerical (also called quantitative) features, on the other hand, have mathematical meaning as a measurement and, of course, are ordered. For instance, term frequency and the tf-idf variant are discrete and continuous numerical features, respectively; the cardiotocography...