被这道题弄的彻彻底底晕了，OG13 77 ！ 什么意思啊

ianwyb

B排除了超速了但是没被抓住的情况 。如果吃罚单的不是经常超速的，那有可能装雷达的就是被冤枉的，偶尔超速被抓，不能得出装雷达的经常超速的结论。

meiyw

我怎么思路完全不同呀。。OG不是说从一个地区的样本扩大到general吗，也就是证明被罚单的人普遍容易超速。。

gogoGMAT720

HarrisZheng 发表于 2012-9-24 14:21
哪有那么复杂？还画柱状图？就是个简单的搭桥过程第一句话是说：所有的车里有3%装雷达，超速被抓（ticketed ...

Mark一下！               

frankzheng43

adamzjw 发表于 2013-4-26 20:18
我也是看了论坛大神们的讨论，一头雾水。后来自己想了一下，其实这题非常简单。
解题思路类似5楼和7楼：

同意！

DannieDeCastle

感谢分享！               

einfucs

adamzjw 发表于 2013-4-26 20:18
我也是看了论坛大神们的讨论，一头雾水。后来自己想了一下，其实这题非常简单。
解题思路类似5楼和7楼：

Mark一下！               

JuliaC2017

感谢分享！               

TuesdayA

meiyw 发表于 2016-12-19 23:09
我怎么思路完全不同呀。。OG不是说从一个地区的样本扩大到general吗，也就是证明被罚单的人普遍容易超速。 ...

我也认为这题考察的是样本具有代表性，argument里的关键词是regularly。

sherry1208

https://www.manhattanprep.com/gmat/forums/a-recent-report-determined-that-although-only-three-percent-t962.html

Summary:
3% of all equipped with detectors
33% of vehicles caught speeding equipped with detectors
Conclusion: drivers who use detectors are more likely to speed regularly than those who don't

Author has made a leap between speeding only occasionally and getting (unluckily) caught vs. speeding regularly - but the rest of the argument does not actually mention anything about the frequency of speeding of various groups. It may be obvious that the more often you speed, the more chances you have to get caught - but the argument does not spell this out.

Choice A does not address author's conclusion - he's contending that drivers who choose to use detectors do so because they plan to speed regularly. This choice says that whether someone has a detector has a bearing on whether s/he gets caught - which may be true in the real world, but it does not answer this question.

Choice B addresses this leap that the author makes about the frequency of speeding. If drivers who are ticketed are likely to exceed the speed limit regularly, then the 33% of vehicles caught speeding with detectors will fall into this category of people who are more likely to speed regularly. Remember, again, that it may be obvious that the more often you speed, the more likely you are to get caught - but the argument doesn't literally spell it out, and that's the point. The author is just assuming this point is true without spelling it out.

所以这题的gap是“超速被罚款”和结论里的“regularly超速”之间的gap吧

题目说了33%超速被罚款的人装了雷达，结论却是装了雷达的人更经常超速

-->因为超速被罚款不等于经常超速，也有可能一些倒霉的人第一次超速就被罚款了，所以gap就是超速被罚款的人比没有被罚款的人更regularly超速-->B

Ron："drivers who speed" 不等于 "drivers who receive speeding tickets". / for instance, you have to think of, say, "murderers" and "people convicted of murder" as COMPLETELY DIFFERENT unless the passage states their equivalence.