扫描二维码，直接登录
题库 / GMATLA-CR-92
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 employees in major zoos, about 30 percent 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 percent but substantially more.
Which of the following, if true, provides the strongest grounds for the experts' conclusion?
A zoo employee who develops a serious animal-induced allergy is very likely to switch to some other occupation.
A zoo employee is more likely than a person in the general population to keep one or more animal pets at home
The percentage of the general population whose level of exposure to animals matches that of a zoo employee is quite small.
Exposure to domestic pets is, on the whole, less likely to cause animal-induced allergy than exposure to many of the animals kept in zoos.
Zoo employees seldom wear protective gear when they handle animals in their care.
这题是CR里的难题，但凡是可以确认推理模式的，就应该执行标准的做题步骤，先改写成标准的conclusion: 动物园工作的人里有30%过敏，人群中一样时间的人也有30%过敏 （样本被放大，统计枚举）套CQ: 正确答案必须涉及样本：动物园工作的人，剩下ABE， BE很清楚是方向反了，模考时排除法选A。
若要正面去理解A：假设整个population里面 有且只有在Zoo工作过的N人 spend a similarly large amount of time in close contact with animals，样本是当前在Zoo工作的n人，其中0.3n过敏，A还给了一个可以用的条件：样本外的N-n个人全部过敏，
所以 population里的百分比是 ((N-n)+0.3n)/N = 1 - (0.7n/N) > 0.3， 因为 n/N
登录 或 注册 后可以参加讨论