Misleading Data and Critiquing

Being able to spot misleading statistics and evaluate claims is a key skill for Edexcel GCSE Mathematics. Questions on this topic appear across all three papers and require you to think critically about how data is presented.

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Key Vocabulary

Term	Definition
Misleading graph	A graph drawn in a way that gives a false impression of the data
Bias	A systematic error that makes results unrepresentative
Leading question	A question worded to influence the answer
Reliability	Whether results would be similar if the study were repeated
Validity	Whether the study measures what it claims to measure

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Misleading Graphs

Common Tricks

1. Not starting the y-axis at zero (a broken axis)

If the vertical axis starts at, say, 50 instead of 0, small differences look much larger.

Example: Sales in January = 52, February = 55. With a y-axis from 50 to 56, the increase looks dramatic. With a y-axis from 0 to 60, it is clearly small.

2. Unequal scales or intervals on axes