PT48, S4, Q19 Fifty chronic insomniacs participated in a one

[bbirdwell]

19. (D)
Question Type: Explain a Result
A group of insomniacs are being studied for one month at an institute. Half are given a new drug, half are given a placebo. The results for both groups are exactly the same: 80% report relief in the first two weeks, and then, in the third week, 90% of that 80% report a return of their insomnia. The correct answer choice must explain this unexpected result _ that both the placebo group and the drugged group had the same results of relief for two weeks and then a return. We need an answer choice that both explains why the drug and placebo have the same effect and why that effects seems to wear off.

Correct answer (D) opens the possibility that the first two weeks were good because insomniacs sleep better in new environments (the institute), and it effectively equates the placebo with the new drug by stating that the drug, like a placebo, is totally ineffective.

(A) is incorrect because it does not address the placebo group.
(B) is incorrect because, while it explains why the placebo may have worked, it does not explain why both groups’ symptoms returned after two weeks.
(C) is incorrect because it does not address the placebo group.
(E) is tempting because it seems to disqualify the study participants _ especially if we carefully read that the study relied on the groups reports. This choice is incorrect, however, because it only discusses "some" insomniacs. Perhaps that refers to a small percentage of insomniacs. We need an explanation that accounts for 80% and 90% of a test sample. (D), with "most", is thus a much stronger answer.