Comparing sets of data for 11+ maths
21 October 2026
Why comparing data matters
Comparing sets of data is a key skill in the 11+ maths exam. Children are often asked to look at tables, charts or lists of numbers and decide which set has higher scores, more consistency or different patterns.
What your child needs to know
To compare datasets, children need to understand how to find and use the mean (average), median (middle value) and mode (most common value). They may also need to look at the range, which shows how spread out the numbers are.
Worked example
Let's look at two sets of scores:
Dataset A: 5, 7, 8, 6, 7 Dataset B: 6, 6, 7, 8, 9
Mean for A: (5 + 7 + 8 + 6 + 7) ÷ 5 = 33 ÷ 5 = 6.6
Mean for B: (6 + 6 + 7 + 8 + 9) ÷ 5 = 36 ÷ 5 = 7.2
Median for A: The middle value is 7 Median for B: The middle value is 7
Mode for A: 7 (appears twice) Mode for B: 6 and 7 (each appears twice)
Range for A: 8 - 5 = 3 Range for B: 9 - 6 = 3
How to compare the results
Both datasets have the same median and range, but Dataset B has a higher mean. Dataset B also has two modes, while Dataset A has one. This suggests that while the middle scores are similar, Dataset B's overall scores are slightly higher and more varied at the top end.
Building confidence with practice
Regular practice with different datasets helps children spot patterns and make comparisons quickly. This builds confidence for the types of questions they will see in the 11+ exam.
Key insight: Understanding and comparing the mean, median and mode makes it easier for children to analyse data and answer 11+ maths questions with confidence.
