本贴相关题目 OG-2015-CR-77 | GMATPrep-2007E2-CR-40OG-2015-CR-77 |
OG-13-CR-77 |
OG-12-CR-78 |
GMATPrep-2007E2-CR-40
... (KLMT)

00:00:00

A recent report determined that although only 3 percent of drivers on Maryland highways equipped their vehicles with radar detectors, 33 percent of all vehicles ticketed for exceeding the speed limit were equipped with them. Clearly, drivers who equip their vehicles with radar detectors are more likely to exceed the speed limit regularly than are drivers who do not.

The conclusion drawn above depends on which of the following assumptions?

ADrivers who equip their vehicles with radar detectors are less likely to be ticketed for exceeding the speed limit than are drivers who do not.
BDrivers who are ticketed for exceeding the speed limit are more likely to exceed the speed limit regularly than are drivers who are not ticketed.
CThe number of vehicles that were ticketed for exceeding the speed limit was greater than the number of vehicles that were equipped with radar detectors.
DMany of the vehicles that were ticketed for exceeding the speed limit were ticketed more than once in the time period covered by the report.
EDrivers on Maryland highways exceeded the speed limit more often than did drivers on other state highways not covered in the report.

正确答案: B

OG12-78

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baozifisher

楼主

发表于 2009-12-21 16:01:14 | 显示全部楼层

我一开始看这题，也很纠结。后来多看了两遍OG的解释，就明白了。

其实是我们没有看懂题目的意思？

drivers who equip their vehicles with radar detectors are more likely to exceed the speed limit regularly
than are drivers who do not. 要注意regular.

题目的意思是- 最近某个高速公里33%被抓的人，都装了radar. 所以装rader的人平常就比较爱超速，和不装的人对比。

这里有个GAP,在这个高速被抓33%比较多，不表明平时这些人都爱超速呀。从特例到一般，除非特别的某个性质可以推导到一边化。在这题里，就是被抓的人本来就爱超速。所以无论在高速上，还是在其他情况下。

-- by 会员 daliliu (2009/11/25 14:21:18)

我同意daliliu 的意见，抓住"regularly"是对的，regularly 意为通常，经常之意。

题目的意思是：装雷达的司机人数占总司机人数的3%，而最近某个高速公路33%被罚的人，都装了radar. 所以装radar的人和没有装Radar的人对比（than are drivers who do not )，通常比较爱超速。

先让我们看看，哪些地方能推翻此结论：

1.样本的因素，即样本是否能反映整体的情况，具体来说，是否在很多其他高速路或公路上都有类似情况发生，非孤例。2.个体的因素，被罚的人仅仅只是这一次的行为或是多次的行为。

以上两条任何一条都可以得出“被罚的人爱超速”不成立，进而结论（装Radar的人通常爱超速）不成立。那么要让结论成立必然要把上述因素排除掉，“被罚的人通常就是比不被罚的人爱超速”一旦成立则结论也成立。