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标题: 【求助】PREP1-58(以前的讨论太不清楚了) [打印本页]

作者: glitters    时间: 2010-3-14 18:26
标题: 【求助】PREP1-58(以前的讨论太不清楚了)

58.   (34705-!-item-!-188;#058&007581)

Roland:  The alarming fact is that 90 percent of the people in this country now report that they know someone who is unemployed.

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 1 out of 20 workers unemployed.  So at any given time if a person knows approximately 50 workers, 1 or more will very likely be unemployed.

Sharon:  But a normal, moderate level of unemployment is 5 percent, with 1 out of 20 workers unemployed.  So at any given time if a person knows approximately 50 workers, 1 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% 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

谁能比较清楚的解释一下B呀,多谢了!

                                                       

作者: hughlv    时间: 2010-3-14 18:36
从题意可知,Sharon的论点有个很关键的前提就是失业人口在全国范围的平均分布。如果失业人口都集中在某一个地理隔离的省,那么理论上只有这个省的人认识失业的人,而这个省的人口是不会超过全国总人口的90%。

B描述的就是这个反例。如果这个反例成立那么Sharon的论点就不正确了。
作者: glitters    时间: 2010-3-14 18:55
有一点明白了,谢谢楼上!
作者: rainbowmanutd    时间: 2010-3-21 10:52
从题意可知,Sharon的论点有个很关键的前提就是失业人口在全国范围的平均分布。如果失业人口都集中在某一个地理隔离的省,那么理论上只有这个省的人认识失业的人,而这个省的人口是不会超过全国总人口的90%。

B描述的就是这个反例。如果这个反例成立那么Sharon的论点就不正确了。
-- by 会员 hughlv (2010/3/14 18:36:42)



可B得意思就是  不是均匀分布啊~~~不应该是取非  削弱吗 ,你的意思是B不取非就削弱了呀。
作者: zzloveyibo    时间: 2014-3-17 13:07
文章问的时S的assumption。

也就是说选项取非要能削弱S的说的话。

那么就来总结一下S说的话。

S:正常的失业率是5%,即每20个人中又1个人失业-->如果一个人认识50个人,那这里一定有1个以上的人失业

B取非后是:unemployment is normally concentrated in geographically isolated segments of the population.

B的意思是说失业通常都是集中在一个偏僻的地方,也就是说,基本上失业就在一个地方很多,而在其他地方很少。如果你采取的样本是在失业很少的地方的话,那就推不出S的结论。所以削弱。有因无果。




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