Easy -1.8 This is a straightforward statistics question testing basic understanding of sampling bias. Students only need to identify obvious sources of bias (time/location exclusion, self-selection, online-only access) with no calculations or complex reasoning required. This is simpler than typical A-level questions.
A researcher wants to find out how many adults in a large town use the internet at least once a week. The researcher has formulated a suitable question to ask.
For each of the following methods of taking a sample of the adults in the town, give a reason why the method may be biased.
Method A: Ask people walking along a particular street between 9 am and 5 pm on one Monday.
Method B: Put the question through every letter box in the town and ask people to send back answers.
Method C: Put the question on the local council website for people to answer online. [3]
E.g. Those who use the internet more frequently are
Answer
Marks
more likely to see the question.
B1
B1
B1
Answer
Marks
[3]
2.4
2.4
Answer
Marks
Guidance
2.4
n
10
0
3
Question 10:
10 | Method A - E.g. Will not sample people who work
then/people who do not walk down that street.
Method B - E.g. This will only get answers from
those who want to send in an answer.
Method C - E.g. This will only get answers from
those who use the council website.
E.g. Those who use the internet more frequently are
more likely to see the question. | B1
B1
B1
[3] | 2.4
2.4
2.4 | n
10 | 0 | 3 | 0 | 0 | 3 | 0
A researcher wants to find out how many adults in a large town use the internet at least once a week. The researcher has formulated a suitable question to ask.
For each of the following methods of taking a sample of the adults in the town, give a reason why the method may be biased.
Method A: Ask people walking along a particular street between 9 am and 5 pm on one Monday.
Method B: Put the question through every letter box in the town and ask people to send back answers.
Method C: Put the question on the local council website for people to answer online. [3]
\hfill \mbox{\textit{OCR MEI Paper 2 Q10 [3]}}