OG13一道百思不得其解逻辑题 跪求大牛指导

kevinlovett

Roland: The alarming fact is that 90 percent of the people in this country now report that they know someone who is unemployed.
Sharon: But a normal, moderate level of unemployment is 5 percent, with one out of 20 workers unemployed. So at any given time if a person knows approximately 50 workers, one or more will very likely be unemployed.
Sharon’s argument relies on the assumption that
(A) normal levels of unemployment are rarely exceeded
(B) unemployment is not normally concentrated in geographically isolated segments of the population
(C) the number of people who each know someone who is unemployed is always higher than 90 percent of the population
(D) Roland is not consciously distorting the statistics he presents
(E) knowledge that a personal acquaintance is unemployed generates more fear of losing one’s job than does knowledge of unemployment statistics
答案是B 但是我始终看不明白这道题在说什么 跪求牛牛们帮我翻译一哈，解释给我听一哈 谢谢啦！

滨崎步祝

R：一个令人担忧的事实：这里90%的人现在都说他们认识的人中有失业的。
S：但是失业率的正常水平是5%，就是20个有1个失业。所以在任何时间如果一个人认识大概50个人，那么其中一个或以上会是失业的。

所以S就是假设失业是平均分布的，不会集中在独立的一群人里面

kevinlovett

滨崎步祝 发表于 2013-7-19 12:01
R：一个令人担忧的事实：这里90%的人现在都说他们认识的人中有失业的。
S：但是失业率的正常水平是5%，就是 ...

THX 我终于明白了 谢谢啦