新PREP 72 不懂不懂，帮忙看看呀

emilyz0301 · 发表于 2011-3-10 21:49:49

72. (30176-!-item-!-188;#058&005083)

Astudy followed a group of teenagers who had never smoked and tracked whetherthey took up smoking and how their mental health changed. After one year, the incidence of depressionamong those who had taken up smoking was four times as high as it was amongthose who had not. Since nicotine incigarettes changes brain chemistry, perhaps thereby affecting mood, it islikely that smoking contributes to depression in teenagers.
Whichof the following, if true, most strengthens the argument?
A. Participants who were depressed atthe start of the study were no more likely to be smokers after one year thanthose who were not depressed.
B.The study did not distinguish between participants who smoked only occasionallyand those who were heavy smokers.
C.Few, if any, of the participants in the study were friends or relatives ofother participants.
D.Some participants entered and emerged from a period of depression within theyear of the study.
E.The researchers did not track use of alcohol by the teenagers.
这个为什么选A呢，我实在想不通，哪位清楚的帮忙讲讲呀，大谢！！！

sdcar2010 · 发表于 2011-3-11 04:55:51

Sample representativeness.

Whenever there is a survey or statistical analysis, one needs to have confidence of the data collected.

Let's look at the following statement: people who spends more time on CD.com can get higher GMAT scores.

To strengthen this statement, you can say:
Two groups of randomly selected students from Beida. At the start, the two groups have comparatively similar GMAT diagnostic scores then one group was sent to the library to study without access to CD.com while the other was sent to the classroom with access to CD.com. The latter groups scores much higher scores in the second GMAT mock test.

To weaken this statement, you can say:
People who spends more time on CD tend to be NN who have higher GMAT diagnostic scores to begin with when compared with the average GMAT participants.

Choice A simply vouchers for the representativeness of the data by removing the potential bias when selecting the participants.

carolfeng · 发表于 2011-3-25 10:31:13

我觉得A的意思不太对啊
开始试验的时候，忧郁的参与者不会比不忧郁的参与者更容易成为吸烟者。
而strengthen应该是：一年后吸烟的人在开始试验的时候和不吸烟的人的忧郁程度一样~
求解

sdcar2010 · 发表于 2011-3-25 10:44:55

LS, the conclusion is that smoking is likely to contribute to depression in teenagers. The premise is that more NEW smokers are depressed than non-smokers. The argument wants to say that smoking CAUSES depression.

But what if it is the other way around? What if depressed people are more likely becoming smokers than non-depressed peopl?

Choice A removes that possibility, thus a correct answer for this strengthener question.

bmwsherry · 发表于 2011-4-29 15:04:44

yeah i get it. Thanks a lot!

新PREP 72 不懂不懂，帮忙看看呀

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