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标题: 请教大全-2-14 [打印本页]

作者: joywzy 时间: 2003-4-13 17:37
标题: 请教大全-2-14
14. A recent survey of all auto accident victims in Dole County found that, of the severely injured drivers and front-seat passengers, 80 percent were not wearing seat belts at the time of their accidents. This indicates that, by wearing seat belts, drivers and front-seat passengers can greatly reduce their risk of being severely injured if they are in an auto accident.

The conclusion above is not properly drawn unless which of the following is true?

(A) Of all the drivers and front-seat passengers in the survey, more than 20 percent were wearing seat belts at the time of their accidents.
(B)Considerably more than 20 percent of drivers and front-seat passengers in Dole County always wear seat belts when traveling by car.
(C) More drivers and front-seat passengers in the survey than rear-seat passengers were very severely injured.
(D) More than half of the drivers and front-seat passengers in the survey were not wearing seat belts at the time of their accidents.
(E) Most of the auto accidents reported to police in Dole County do not involve any serious injury.

答案：A。也是有关数字的假设题。我有点晕。不知从何处着手。谢谢。

作者: cranberry 时间: 2003-4-13 19:52
题干的意思是“全部伤者中重伤号里，80%是不带安全带的。所以如果带安全带，那么会大大减小其事故里被重伤的几率。”实际是找支持的事实，如何找呢？那么必须找到一个事实，来说明只是因为带了安全带而不是别的原因导致了不同的结果。A的意思是“实际不带安全带的人只占了全部伤者的70%多，但却占了重伤者的80%”说明，安全带带与不带还是有差别的。不知是否有帮助。

作者: joywzy 时间: 2003-4-13 20:03
完全同意啊！！

可是我自己一个人如果在考场能想明白这些吗？？？！！！

作者: dingxiang 时间: 2008-5-4 13:07

以下是引用cranberry在2003-4-13 19:52:00的发言：
题干的意思是“全部伤者中重伤号里，80%是不带安全带的。所以如果带安全带，那么会大大减小其事故里被重伤的几率。”实际是找支持的事实，如何找呢？那么必须找到一个事实，来说明只是因为带了安全带而不是别的原因导致了不同的结果。A的意思是“实际不带安全带的人只占了全部伤者的70%多，但却占了重伤者的80%”说明，安全带带与不带还是有差别的。不知是否有帮助。

看了几个讨论贴, 有对这道题画图的, 有用数学推理的, 但考试时候明显不可能做到,还是cranberry 解释的最清楚!

大家都在讨论A, 很少讨论D选项

在我看来,A 与D是两个极易混淆的选项:

A选项cranberry 已经解释的很清楚了

对于D, 说 >50%的人没有带安全带, 但是并没有对>50% 设一个上限, 举个例子如果说是90%的受伤者没有带安全带, 与题干相比较,(受重伤者中80%的人没有带安全带), 也就可以推出其实不带安全带受轻伤的比例小于受重伤的, 也就是带安全带没这么大用处. 所以D是个混淆项

综上所述, 只要保证所有受伤者中不带安全带比例小于重伤者中不带安全带的比例就可以成为这道题目的假设.

具体的从数字比例上来说就是

在区间所有受伤者中不带安全带比例<80%, 也即所有受伤者中带安全带比例>20%,则都可以作为正确选项

寒自己一个, 好像说来说去都在说一句话

[此贴子已经被作者于2008-5-4 14:20:50编辑过]

作者: xiaok5757 时间: 2009-2-28 13:25
真是经典，终于明白了，谢谢

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