xdf蓝皮书29

marian_w

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！

fiona9179119

题目说了sample 是30% 而population 是不只30% 所以说A对

ningleena

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

marian_w

嗯，知道了，谢谢ningleena   和 fiona9179119！！

skyzhang

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。

crystal007

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%。