To compare two sets of data, use one average (like the mean or median) and one measure of spread (like the range). The average tells you which group did better overall. The spread tells you which group was more consistent.
Group P's marks have median 54 and range 49. Group Q's have median 33 and range 34. So Group P did better on average, but Group Q's marks were more consistent. Always write your comparison in the context of the question.
Worked example
Class A has mean 62 and range 30. Class B has mean 58 and range 12. Compare them.
- Average: Class A's mean is higher, so A did better on average.
- Spread: Class B's range is smaller, so B was more consistent.
Answer:A did better on average; B was more consistent.
Key words
- compare
- say how two groups are alike or different
- consistent
- values close together
- context
- what the numbers are about
Practise this
New questions every time.
Common Core-referenced: 7.SP.B.3