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AQA GCSE · Question 17.2 · Data Collection and Sampling Methods
Here is one of the questions from Tom's study. Write down two different problems with this question.
Question: "How old are you? Tick a box: [ ] under 21 [ ] 21-50 [ ] 51-60 [ ] 61-70"
Here is one of the questions from Tom's study. Write down two different problems with this question.
Question: "How old are you? Tick a box: [ ] under 21 [ ] 21-50 [ ] 51-60 [ ] 61-70"
How to approach this question
When critiquing a questionnaire question, look for common flaws:
1. **Exhaustive options:** Do the options cover all possible answers? What if someone is older than 70?
2. **Mutually exclusive options:** Can someone fit into more than one category? What if someone is exactly 21? (The question says "under 21", so 21 would go in the next box. The boxes are exclusive. So this is not a problem).
3. **Equal group widths:** Are the ranges of the groups similar in size? Compare the size of the "21-50" group with the "51-60" group.
4. **Leading or biased wording:** Is the question phrased neutrally? (This doesn't apply here).
Identify two of these issues.
Full Answer
Problem 1: The age groups are overlapping. A person who is 21 could tick the "under 21" box or the "21-50" box. This is not clear. A better way to write this would be "21 or under". However, the main issue is the groups are not exhaustive.
Problem 1: The age groups are not exhaustive. There is no box for people over 70.
Problem 2: The age groups are of unequal width (e.g., 21-50 is a 30-year span, while 51-60 is only a 10-year span). This makes comparing the groups difficult.
There are several problems with this question design:
1. **Problem 1: The response boxes are not exhaustive.** The options only go up to age 70. There is no option for anyone aged 71 or older, so they cannot answer the question. All possible ages should be included.
2. **Problem 2: The groups have unequal widths.** The "under 21" group is 21 years wide. The "21-50" group covers a 30-year range. The "51-60" group covers a 10-year range, and "61-70" covers a 10-year range. These unequal class intervals make it difficult to analyse the data fairly or to represent it in a histogram.
(Note: The boxes are mutually exclusive. "under 21" means up to 20. So someone who is 21 would tick the "21-50" box. So overlapping boxes is not an error here).
Common mistakes
✗ Stating the boxes are overlapping. "Under 21" does not include 21.\n✗ Giving two examples of the same problem (e.g., "no box for 71" and "no box for 80" are both the same "not exhaustive" issue).
Practice the full AQA GCSE Statistics Foundation Tier Paper 2
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