Digital PSAT Math Practice Question 98: Answer and Explanation

Question: 98

A scientist surveys 16 randomly selected teenage students, recording their ages and their average number of hours of nightly sleep.

Which of the following would most likely cause the greatest obstacle to the accuracy of the sleep survey results?

• A. If the student survey responses are self-reported
• B. Whether the survey was conducted during the school year or during summer break
• C. If not all of the 16 teenagers respond
• D. If the scientist misreads the number of hours of one responder and records one more hour of sleep on average than what was reported

Correct Answer: A

Explanation:

(A) Students may be entirely unaware of how many hours they're sleeping. Alternatively, they may modify their answers for a variety of reasons, possibly to give the answers they suspect the researchers want to hear. This makes self-reporting a fairly inaccurate technique, as in choice (A).

Choice (B) isn't correct because, although students may get a different number of hours of sleep during the school year versus the summer, the study asks for the average number of hours. This should take into account variations due to time of year.

Choice (C) isn't correct because the researchers could simply ask more teenagers.

Choice (D) isn't correct because changing one response by a small margin shouldn't have a large result on the accuracy of the entire study.