请教各位一道题，真的快被憋死了

heavenlam

a recent survey of all auto accident victims in melen 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.

which of the following, if true, is the assumption that the argument above is based on?

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 melen county usually use their cell phones when traveling by cars.
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.

答案就是选A，真的是百思不得其解，请各位高手帮忙解释一下吧。谢谢~~~

heavenlam

我的理解是不是说 因为那80%是severely injured里的，所以不能说明包括不是severely injured在内的all drivers都寄上安全带就可以避免severe injure，但是还是想不通答案为什么是A

Fiona09

题干的意思是说：全部伤者中的重伤者里，有80%是不系安全带的。所以如果系了安全带，那么其事故里被重伤的几率就会大大减少。

实际是找支持的事实，要如何找呢？

必须找到一个事实，来说明仅仅是因为系安全带，而不是别的原因，才导致了这样不同的结果。选项A，是说——实际不系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，这说明了系安全带与不系安全带还是有非常明显的差别的。

也不知道我说清楚了木有。。。

VincentFSJ

其实就是受重伤的里面有百分之八十是不系安全带的
p：车祸重伤的百分之八十不系安全带
c：系安全带保安全
缺一个假设
那么假设是什么？就是所有开车的和坐前排的中，不低于百分之80都系了安全带，不然怎么说明系安全带更安全。
建议你排开自己看题时候的脑子里的假设，一看到安全带就觉得安全带更安全（可能你看到题干的时候就假设了几乎所有坐前排的人都系了安全带）’

heavenlam

heavenlam 发表于 2016-9-4 00:36
我的理解是不是说 因为那80%是severely injured里的，所以不能说明包括不是severely injured在内的all driv ...

这样说我就比较懂了，虽然这道题如果按样本的有效性来排除的话是可以秒选，但是根本看不懂A的逻辑。谢谢~

heavenlam

heavenlam 发表于 2016-9-4 00:36
我的理解是不是说 因为那80%是severely injured里的，所以不能说明包括不是severely injured在内的all driv ...

不过，A跟D选项的差别能再进一步帮忙解释一下吗？

heavenlam

heavenlam 发表于 2016-9-7 23:34
不过，A跟D选项的差别能再进一步帮忙解释一下吗？

和D的差别还想不太清楚