Definition
Categorical data
Categorical data uses labels or groups, such as colour, shape, or transport type.
What it means
Categorical data answers “which kind?” A response such as bus, walk, or car names a group, not an amount to calculate with. You can count how many responses fall in each category and show those counts in a table, pictogram, or bar chart.
Remember it
Ask “which kind?” and sort each answer into a named box.
Example
Six lunch choices are rice, noodles, rice, soup, noodles, and rice. These are categorical data. Counting them gives rice 3, noodles 2, soup 1.
Watch for
A code such as route 1 or route 2 can still be categorical when the numbers are only labels and arithmetic on them has no meaning.
Common mix-up
The category counts are numerical summaries, but the original values remain categorical labels.
Exact meaning
Categorical data consists of observations whose values identify groups or qualities; even a number is categorical when it acts only as a label.