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标题: xdf蓝皮书29 [打印本页]

作者: marian_w    时间: 2009-3-13 11:05
标题: xdf蓝皮书29

29.People who have spent a lot of time in contact with animals often develop animal-induced allergies,some of them quite serious.In a survey of current emplyees in major zoos,about 30% had animal-induced allergies.Based on this sample,experts conclude that among members of the general population who have spent a similarly large amount of time in close contact with animals,the percentage with animal-induced allergies is not 30% but substantially more.

Which of the following,if true,provides the strongest grounds for the experts' conclusion?

A.A zoo employee who develops a serious animal-induced allergy is very likely to switch to some other occupation.

B.A zoo employee is more likely than a person in the general population to keep one or more animal pets at home.

C.The percentage of the general population whose level of explosure to animals matches that of a zoo employee is quite small.

D.Exposure to domestic pets is less likely to cause animal-induced allergy than exposure to many of the animals kept in zoos

E.Zoo employees seldom wear protective gear when they handle animals in their care.

答案是A,我也选对了,但是是因为其他选项根本就不沾边,请教大家为什么A对了。谢谢!


作者: fiona9179119    时间: 2009-3-13 12:46
题目说了sample 是30% 而population 是不只30% 所以说A对

作者: ningleena    时间: 2009-3-13 19:21

我是这样理解的,对于无论是在动物园工作的人还是对在其他岗位工作的人来说,如果和动物相处同样多的时间,对动物的过敏程度是相同的,都是人。

在动物园工作的人,正如 A 所讲,如果严重过敏就会转到其他职位去工作,这样其他岗位工作的人对动物过敏的百分比率就会增加,所以要高于30%,就加强了观点


作者: marian_w    时间: 2009-3-13 21:52

嗯,知道了,谢谢ningleena   和 fiona9179119!!


作者: skyzhang    时间: 2009-4-24 13:11

刚好做到这个题目。

是不是应该说:

动物园的人过敏马上就换工作。

有可能动物园的人是100%过敏,只是因为过敏了马上换工作,新来的人还没有过敏,所以看起来好像只有30%。实际上那些新来的人过不了多久也会过敏。


作者: crystal007    时间: 2009-4-24 14:43
我觉得skyzhang想复杂了。没有理由假设动物园的人过敏率是100%。而且也不需要这样假设。只是因为动物园的工作人员过敏会换工作,所以among the members of the population who have a similarily large amount of time in close contact with animals,过敏率会高过30%。




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