When data is grouped, the median isn’t a value — it’s a class. Full four-page lesson on modal class, median class and max/min range from grouped frequency tables. OCR GCSE Foundation, Unit 7 Lesson 7.

What’s included

• I Do and We Do with cumulative frequency columns built step-by-step
• Two independent practice tasks deliberately contrasted: Task A has modal class ≠ median class; Task B has them equal — pupils must verify via n ÷ 2 every time, not copy across
• Three-misconception Spot the Mistake — each Sam item targets one core confusion: frequency-as-modal-class, row-count median, range-from-frequencies
• Going Deeper: inverse table construction + the conceptual why “median class” not “median value”?
• Exit Ticket with odd n = 27 to address the n ÷ 2 = 13.5 hesitation

Teacher key (6 pages)

• Full CF columns and answers across all 5 datasets
• Section-by-section pedagogical notes and watch-fors
• OCR M1/A1 mark scheme guidance per skill, including common mark losses
• Diagnostic-for-marking patterns — what each wrong answer tells you
• Marking summary table across all five datasets

smartle. @Smartle-Maths