都是归纳里面的题，我做weaken还挺顺的，怎么到了归纳就转不过弯来了呢？还请各位赐教
1. Recent estimates predict that between 1992 and 1995 the greatest increase in the number of people employed will be in the catagory of low-paying service occupations. This category, however, will not increase its share of total employment, whereas the category of high-paying service occupations will increase its share.
If the estimates above are accurate, which of the following conclusions can be drawn?
A. In 1992 more people were working in low-paying service occupations than were working in high-paying occupations.
B. In 1995 more peoplewill be working in high-paying service occupations than will be working in low-paying service.
C Nonserice occupations will account for the same share of total employment in 1995 as in 1982.
D.Many of the people who were working in low-paying service occupations in 1982 will be working in the -paying service occupations by 1995
E. The rate of growth for low-paying service occupations will be greater than the overall rate of employment growth between 1982 than 1995.
这道题答案选了A 我是比较了半天也没选出来。 提示说要用数学的方法进行比较。麻烦大家帮我看看哈
2. A recent survey of all auto accident victims in Dole Country found that, of the severely injures drivers and front-seat passengers, 80 percent were not wearing seat belt at the time of their accident. This indicates that, by wearing seat belts, drivers and front-seat passengers can greatly reduce their risk of being severly injured if they are in an auto accident.
The conclusion above is not properly drawn unless which of the following is true(纠结在这里了一开始 是问那个可以支持上的结论对吧？)
A Of all the drivers and front-seat passengers in the survey, more than 20 percent were wearing seat belts at the time of their accident
B. Considerably more than 20 percent of drivers and front-seat passengers in Dole Country always wear seat belt when traveling by car.
C. More than half of the drivers and front-seat passengers in the survey were not wearing seat belts at the time of their accidents.
剩下的两个选项明显不对 就没打上来。
这道题答案选A 我选的C。 我认为归纳就是不能超过原文的范围。所以原文说80% 我这里说half 就应该没有错。 难道这个more than half of 里面有玄机？ 请大家指教
第一个我解释不清楚，
第二个个人认为是假设题，也就是以上的推理基于以下的哪一个假设，
我记得是A答案，如果在所有的人群中既安全带的比例不超过20%的话
说明正常情况下安全带的作用是很小的，因为题目中说的是of the severely injures drivers and front-seat passengers
系安全带的比例不超过20%，如果所有人群的整体都是不超过的，也就是说
系不系安全带对于受伤没有影响，并没使得受伤的比例上升，可以用not 来取反以后检验一下结论就不成立了
（我逻辑很糟糕，但是这个题有好好研究过）
回楼上 首先谢谢你
其次 最后一道题的A翻译过来就是在这个survey中有超过20%的人带了安全带当他们发生事故的时候 好像有点不大对劲啊
第一题可以用数学不等式来证明的
但是不用列公式也可以做出来 低收入人群数有greastest increase 但占总人数的比例没增加 反而高收入的人群所占比例增加了 为什么会出现这种情况呢 唯一可能就是低收入的原来的人多 所以他的增量对比例的影响小
举个最简答的例子 82年一共一共10个人 低8 高2
95年 一共13个人 低10 高3
第二题 这其实问的是assumption
我解释一下A
题目说 在一个调查中 发生车祸导致严重受伤的人中 80%没带安全带，由此他就说带安全带可以降低受重伤的机率 问作者的假设是什么
我们来分析一下 根据题干 我们可以知道在严重受伤的人里面20%带了安全带 那么如果所有受调查的人中 超过20%的人带了安全带 我们就能推断出没受重伤的人里面是有超过20%带了安全带的 也就是说没重伤的人当中 低于80%的人没带安全带 所以 带安全带可以降低受重伤的机率。
我们简单的数字化一下 假定一共200人 25%带了安全带也就是50人 100人受重伤 其中20人带了安全带 另外100人没受重伤 30人（50-20）带了安全带 我们的可以得到 带了安全带的50人里 2/5受重伤 在150个没带安全带的人中 80个人受重伤 8/15 ，2/5显然小于8/15 支持结论----带安全带降低受重伤机率
| 欢迎光临 ChaseDream (https://forum.chasedream.com/) | Powered by Discuz! X3.3 |