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标题: perp2--40,急! [打印本页]

作者: xinglufree    时间: 2009-5-6 22:51
标题: perp2--40,急!

a recent report determined that although only three percent of drivers on maryland highways equipped their vehicles with radar detectors, thirty--three percent of all vehicls ticketed for exceeding the speed limit were equipped with them. clearly, dirvers 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 assuption.

A drivers who equip their vehicles with radar detectors are less likely to be ticketes for exceeding the speed limit than drivers who do not.

B drivers who are ticketed for exceeding the speed limit are more likely to exceed the speed limit regularly than are drivers who are not ticketed

C the number of vehicles that were ticketed for exceeding the speed limit was greater than the number of vehicles that were equipped with radar detectors.

D many of the vehicles that were ticketed for exceeding the speed limit were ticketed more than once  in the time period covered by the report.

E drivers on maryland highways exceeded the speed limit more than did drivers on other state highways not covered in the report.

正确答案是B,请帮忙解释一下原因,谢谢!!!!!!!!!


作者: lollypp    时间: 2009-5-7 05:44

文中说只有3%的人装了radar,然而在因超速被ticketed的人中33%的人都装了radar,结论:装radar的人更容易超速。

B取非:因超速被ticketed的人的更不容易超速,潜台词是因为他们装了radar,是因为他们信任radar而超速的。即排除了司机自己易超速这个他因。






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