Watch out
Calling a group better using spread alone.
Scottish National 5 Mathematics
National 5 Maths Comparing data sets
Compare centre and spread using interquartile range and standard deviation in context.
Formula reference
Check the National 5 rules and formulae linked to this topic.
Which method?
Match exam clues to a suitable method.
Before you start
- Identify what each statistic measures.
- Decide whether a calculator supports the method; exact working may still be required.
- Read the command word, record the units or requested form, and make the final answer match it.
Explanation
Comparing data sets is an assessed part of Scottish National 5 Mathematics in the statistics area. Compare centre and spread using interquartile range and standard deviation in context.
Identify what each statistic measures.
Compare like with like: centre with centre and spread with spread.
State what the numerical comparison means for the named groups.
The interactive bank below mixes direct skills, reverse questions, interpretation and contextual reasoning rather than repeating one number pattern.
Key formulae and rules
- Compare a measure of centre and a measure of spread, then write the conclusion in context.
Check
Check the calculation, then state what the result means for the named data or model rather than treating an estimate as exact.
Exam tip
Quote the relevant statistic or model value, then interpret it in the context of the named data.
Worked examples
Worked example 1
Comparing data sets worked example
Two teams have the same median. A has IQR 6 and B has IQR 11. Compare consistency.
- A smaller IQR means the middle half is less spread.
- Team A has the smaller IQR.
Answer: Team A is more consistent.
Watch out
- Calling a group better using spread alone.
- Repeating numbers without interpreting them.