What are categorical variables?

Categorical variables are defined as variables that can be placed into distinct categories based on qualitative characteristics rather than numerical values. This means that the data can be divided into groups or categories without any inherent order or ranking among them. For example, variables such as gender, eye color, or type of pet fall under this category. Each of these can be classified into specific groups (like male/female or dog/cat) but cannot be measured on a scale or continuum. This classification is fundamental in research, as it allows for the organization and analysis of data based on the qualitative aspects of the variables.

The other options discuss different types of variables, such as continuous variables that can be measured on a continuum or represent numeric values, which would not be applicable to categorical variables. Therefore, the distinction provided in option B accurately captures the essence of what categorical variables are.