Edexcel GCSE Statistics · 1ST0
Specification 1b.02, 2a.04 · Paper 1, Paper 2
Revise: Data grouping implicationsA class interval is a range of values treated as one group. For whole-number test marks, classes such as 20–29, 30–39 and 40–49 work because every mark belongs to only one class. A mark of 29 belongs to 20–29; a mark of 30 belongs to 30–39.
A range of values used to group numerical observations, such as .