Statistics

Statistics within GCSE Maths covers collecting and sampling data, averages and range, frequency tables, and the diagrams used to present data — bar charts, pie charts, scatter graphs, cumulative frequency and box plots, with histograms at Higher tier.

Most questions fall into two halves: calculate something, then interpret it. The calculation is usually straightforward; the interpretation is where marks are won. When comparing two data sets you need both an average and a measure of spread, each stated in the context of the question rather than as bare numbers. Common errors include reading a frequency from the vertical axis of a histogram instead of calculating an area, forgetting that grouped data only gives an estimate of the mean, and plotting cumulative frequency at the midpoint rather than the upper class boundary.