Official Solution:An avid television viewer is statistically more likely to take sleeping pills at bedtime than a person who enjoys listening to classical music but does not watch television as a habit. Clearly, listening to classical music just before bedtime contributes to a more restful night’s sleep, whereas watching television before bedtime has the opposite effect. Which of the following, if true, most seriously weakens the above argument? A. People who enjoy classical music typically like to read just before bedtime.
B. Reading a book before bedtime contributes to restful sleep more than listening to music does.
C. Sleeplessness is more common among people who watch late-night television than among people who do not.
D. Engaging in a bedtime activity that is mentally stimulating often interferes with a person’s ability to fall asleep.
E. A silent environment is less conducive to restful sleep than an environment with calming ambient sounds.
A. Correct. The argument concludes that there is a cause-and-effect relationship between listening to classical music and getting restful sleep. But this conclusion is based merely on the statistical correlation cited in the first sentence. One way to discredit the conclusion is to provide evidence that something else might result in restful sleep. That’s exactly what option A accomplishes, by pointing out another possible cause: bedtime reading.
Please note that the strengthen / weaken questions need not ensure the conclusion (or the error in the conclusion). It should in some way (even if something needs to be assumed) strengthen or weaken. The assumption questions are "must be true" type, but not strengthen / weaken ones. Option A implies that there MAY be some other reason that causes sound sleep - this is good enough to weaken the argument. (It is not required that there MUST be some other reason.) The following example may be useful to understand the reasoning better:
All students of grade 7-A have scored very well. Ms. Danny is their class teacher. She must have taught them very well. Now, what can make me doubt Ms. Danny's role? What if I were told, "All students of grade 7-A take extra classes with Ms. Veronica." Will that make me doubt my conclusion? Yes. I will wonder - is Ms Danny a very good teacher or is it that Ms. Veronica did a great job? It will make me think that my conclusion about Ms Danny may not be valid. That is all we need to do - weaken our conclusion, cast doubt on the conclusion.
Similarly, we are not given that reading leads to better sleep. We don't need to establish it either. We just have to make ourselves doubt the conclusion.
B. Option B must not be mixed up with option A and must be examined independently. Option B draws a comparison between reading books and listening to music. It does not weaken the conclusion of the original passage, which deals with listening to music and watching television. Option B is a supporting statement for option A, which in turn is a weakening statement for the original passage. However, in absence of option A (i.e., independent of option A), option B is not a weakening statement for the original passage.
C. Option C might look tempting at a first look because it appears to establish a reverse causal relationship, but actually it does not. If the statement were something like the one below, then option C would be a weakening statement:
"People who cannot sleep at night watch television to pass time"...such a statement establishes a reverse causal relationship, thereby weakening the forward causal relationship.
However option C implies another correlation, but not a reverse causation.
Moreover option C strengthens a part of the inference: "...whereas watching television before bedtime has the opposite effect". It is a strengthening statement, not a weakening.
D. This option is out of context because it has not been defined, which activities are stimulating and which are not.
E. Option E is also out of context. The argument is about two things: whether listening to classical music is conducive to restful sleep and whether watching television is not. Option E does not deal with any of these two.
Answer: A
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