Categorical variables have labels such as names or types.

• A. Quantitative measures with magnitude.
• B. Variables that have labels rather than numerical magnitudes.
• C. Variables that must be controlled.
• D. Variables that change randomly.

Answer: (B)

Categorical variables are described by labels or names rather than numbers. This means observations are grouped into categories such as eye color, species, or brand, with each category being a label rather than a numerical value. Because there isn’t a meaningful numeric magnitude to these categories, you don’t add or average them. Instead, you count how many observations fall into each category and often present the data with a bar chart or pie chart.

That description—variables that have labels rather than numerical magnitudes—fits this idea exactly, so it’s the best match.

The other descriptions aren’t about the type of data: quantitative measures have numbers and magnitudes you can compare arithmetically, controlled variables describe experimental conditions rather than data type, and changing randomly isn’t a defining feature of categorical data.