Examples

Take marks in a test recorded only as whole numbers (no fractional marks), ranging from 0 to 100 — a discrete variable. Wanting equal-sized intervals and 10 classes, the classes can be written in either form:

Inclusive form: 0–10, 11–20, 21–30, …, 91–100 (both end-values belong to the class).

Exclusive form: 0–10, 10–20, 20–30, …, 90–100 (a value equal to a limit is excluded from that class). …