Author note — to cover

Draw frequency polygons for grouped continuous data by plotting each frequency at its class midpoint and joining with straight segments, with no closing back to the axis at GCSE. Interpret and compare two polygons on one grid. Plotting at boundaries is the classic error to confront. Histogram bars and area are separate pages. Both tiers. (S4)

• Fluency — direct questions on frequency polygons, limited to this lesson's stated scope (4 questions).
• Application — use the same skill in unfamiliar or contextual questions without introducing a later method (4 questions).
• Check — questions built around the exclusions and likely misconceptions named in the lesson brief (4 questions).