16Hit1600
Problem-Solving and Data AnalysisVery hardGeneralising from a survey outside a bicycle shop

Problem-Solving and Data Analysis practice question

To estimate the proportion of a city's residents who cycle to work, a researcher surveys 1,000 people leaving a bicycle shop, and 70 percent say they cycle to work. Which statement about this result is correct?

  1. A. It cannot be generalised to the city's residents, because people leaving a bicycle shop are more likely to cycle than residents in general, regardless of the sample size.Correct
  2. B. It can be generalised, because 1,000 is a large sample.
  3. C. It shows that about 70 percent of the city's residents cycle to work.
  4. D. It can be generalised if the survey is repeated on another day.

Answer: A. It cannot be generalised to the city's residents, because people leaving a bicycle shop are more likely to cycle than residents in general, regardless of the sample size.

A biased sampling method is not fixed by a large sample.

Why the other answers are wrong

B. It can be generalised, because 1,000 is a large sample.
Sample size does not correct a biased selection.
C. It shows that about 70 percent of the city's residents cycle to work.
The 70 percent describes bicycle-shop customers.
D. It can be generalised if the survey is repeated on another day.
Repeating the same biased method gives the same bias.

More Problem-Solving and Data Analysis questions

Not affiliated with the College Board. SAT is a trademark of the College Board.