Comparing Populations Using Diagrams | I Do, We Do, You Do | Year 9 Maths | Print Free

Build confident statistical comparisons with this 85-slide Year 9 PowerPoint. Pupils read diagrams, calculate averages and ranges, and explain what those measures reveal about two groups.

The lesson moves beyond “which average is bigger?” Pupils consider equal means with different spreads, unequal sample sizes, outliers and claims that the data cannot justify. Questions are designed for responses on mini whiteboards or in exercise books, with no pupil printing required.

WHY THIS LESSON WORKS
• Clear scales and visible gridlines require pupils to read values from the diagrams rather than copy labels above the bars.
• Matched I Do / We Do examples cover line graphs, frequency diagrams and back-to-back stem-and-leaf diagrams, using different datasets.
• Questions distinguish typical value from consistency and require numerical evidence for comparisons.
• Frequency-diagram work explicitly addresses weighted totals, pupil counts and the mistake of averaging bar heights.
• A one-page differentiated task keeps the whole class working from the same diagram, with larger versions available when needed.
• Compact answer pages support efficient checking and discussion.

WHAT IS INCLUDED
• Six retrieval starter questions and answers.
• Six prerequisite questions and answers.
• Guidance on comparing averages and spread, reading frequencies and finding a mean from a frequency diagram.
• Three paired I Do / We Do modelling slides, individual examples and worked answers.
• An additional one-page I Do / We Do option for line graphs.
• A scatter-graph example comparing two groups at the same value of the other variable.
• 20 individual AFL questions, each followed by its answer.
• 24 practice questions across clinic waiting times, book borrowing and test scores, with answers.
• A one-page differentiated task containing 6 Developing, 6 Secure and 4 Greater Depth questions, plus a Super Challenge.
• Enlarged differentiated task options and two pages of differentiated answers.
• A Super Challenge exploring how equal means can coexist with different medians and ranges.
• Three exit questions and answers.

MATHEMATICAL FOCUS
Read and compare diagrams; calculate mean, median, mode and range; use frequencies correctly; compare proportions when group sizes differ; interpret consistency; investigate the effect of changing data; and recognise the limits of conclusions drawn from samples.

YOUR DOWNLOAD
An editable 85-slide PowerPoint lesson containing diagrams, questions and answers.

Created by Beyond Printables for Year 9, Unit 24, U520: Comparing Populations Using Diagrams.