曼哈顿一道关于选举的问题

hgjtytryr

In a recent poll, 71% of respondents reported that they cast votes in the most recent national election. Voting records show, however, that only 60 of eligible voters actually voted in that election.
Which of the following pieces of evidence, if true, would provide the best explanation for the discrepancy?

(A) The margin of error for the survey was plus or minus five percentage points.
(B) Fifteen percent of the survey's respondents were living overseas at the time of the election.
(C) Prior research has shown that people who actually do vote are also more likely to respond to polls than those who do not vote.
(D) Some people who intend to vote are prevented from doing so by last- minute conflicts on election day or other complications.
(E) Polls about voting behavior typically have margins of error within plus or minus three percentage points.  
答案是C。 不知道理解的对不对。原文中说71% 人回应他们在选举中会投票，然而实际上只有60%的人真正投票了。C 的意思是说真正投票的人要比那些不投票的人更容易参与调查。言外之意也就是说 这些参与调查的人之中有vote的权利人占了大多数，而没有vote的权利的人占了少数？？因此虽然71%回应说会vote，但是事实上只有60% vote了？？其他选项根据曼哈顿的参考答案可以理解，唯独这个正确答案我有点懵了。请大牛指正！

stellalights

原来如此~~

hgjtytryr

多谢

maxwhite

不要纠结于是否有权利vote，因为C选项并不在说这件事。按照你的理解出现选项F
F. Many people who responded to the poll were not eligible to vote 但是并不是选项C在讲的事情。

选项C在说的意思是，你去农村调查超生，71%的农民说俺们家只生一个，但是人口普查发现，只有60%的农民只生了一个。 原因就是超生的家庭不愿意参加你的调查，或者，没超生的家庭“are also more likely to respond to polls”，所以你的71%的sampling就是biased