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标题: [讨论]本月JJ中"percentage change in numbers of "到底如何理解？ [打印本页]
作者: tangyuehua    时间: 2008-2-28 20:09
标题: [讨论]本月JJ中"percentage change in numbers of "到底如何理解？

[讨论]

本月JJ中"percentage change in numbers of "到底如何理解？我明天就考啦，请高人指点。。。

6．   某城市94-95年的percentage change in numbers of 得了什么病还是干了什么的人？(1)94年该群体占总人口比例61% ，(2)95年该群体占总人口比例73%

理解一：macelino:

percentage change in numbers of，我的理解是百分比的变化情况，而非变化的百分比，那么
            

条件1，只知道94年，不知道changes，不充分
                

条件2，只知道95年，不知道changes，不充分
                

两条件一起考虑，73%-61%=12%，这个就是changes，充分
            

KEY：C

理解二：dawnguo:

我的理解是（请大家讨论指正）：比如的癌症吧。94年100人，95年200人 percentage change in numbers = (200-100)/100*100%=100%. 属于what类型题目。
                    

1）只知道94年，95年信息一点没有，完全not sufficient

2）同上
                    

1+2，设94年95年总人口分别是x，y    (0.73y-0.61x)/(0.61x)*100% 无解
                    

Key：E: together not sufficient, need additional info.

Key：E: together not sufficient, need additional info.

作者: woklovepp    时间: 2008-2-28 21:47

我觉得应该是百分比的变化情况

作者: tangyuehua    时间: 2008-2-28 22:50
我觉得是后者，是说病人数的变化的百分比。这更能体现出本题的TRICK所在！请牛人指点啊！
作者: allenhzkk    时间: 2008-2-28 23:33
理解一默认了两年的人数相等，
理解二觉得两年的人数不等，一般来说，应该是不等的吧，

这种情况要如何处理。
作者: tangyuehua    时间: 2008-2-28 23:52

顶！！！这种题以前肯定有过，请经验丰富的CDer指点。。。

在Google上查了查，有很多PDF的图表，但没有详细的解释。坚持原来的理解，应该是第二种，GMAC真是够阴的。。。

http://www.google.cn/search?q=percentage+change+in+numbers+of+&complete=1&hl=zh-CN&start=0&sa=N

作者: tangyuehua    时间: 2008-2-29 04:50

顶，高人赶紧给个说法。

作者: macelino    时间: 2008-2-29 09:54
以下是引用tangyuehua在2008-2-28 23:52:00的发言：

顶！！！这种题以前肯定有过，请经验丰富的CDer指点。。。

在Google上查了查，有很多PDF的图表，但没有详细的解释。坚持原来的理解，应该是第二种，GMAC真是够阴的。。。

http://www.google.cn/search?q=percentage+change+in+numbers+of+&complete=1&hl=zh-CN&start=0&sa=N

图表里都是百分比变化，并未涉及总量。故直接比较百分比就好。
作者: AlienX    时间: 2008-2-29 10:24
Today, I just did one DS in PowerPerp3(PP3), and it is the latter one.
I will try to post the question later.
作者: AlienX    时间: 2008-2-29 10:31
As promised, here you go:

From 1984 to 1987, the value of foreign goods consumed annually in the United States increased by what percent?
1. In 1984 the value of foregin goods consumed constituted 19.8 percent of the total value of goods consumed in the United States that year.
2. In 1987 the value of foregin goods consumed constituted 22.7 percent of the total value of goods consumed in the United States that year.

The official answer is E.

Maybe a similar question, maybe not
作者: macelino    时间: 2008-2-29 10:55
以下是引用AlienX在2008-2-29 10:31:00的发言：
As promised, here you go:

From 1984 to 1987, the value of foreign goods consumed annually in the United States increased by what percent?
1. In 1984 the value of foregin goods consumed constituted 19.8 percent of the total value of goods consumed in the United States that year.
2. In 1987 the value of foregin goods consumed constituted 22.7 percent of the total value of goods consumed in the United States that year.

The official answer is E.

Maybe a similar question, maybe not

BY WHAT PERCENT 当然要考虑总量问题

但是 PERCENT CHANGE IN THE NUMBER 是在问百分比的变化，与总量无关。请看前面几楼有一位CDer帖的GOOGLE帖。

作者: jerry_su2000    时间: 2008-3-1 01:58

应该是第二种解释，人数变化的百分比。

反正法：
如果是第一种解释，必须存在前后两个百分比，要定义这两个百分比，必须有一个新的范围，题中的这个新范围就是总人数。其实如果没有总人数这个范围，前后两个百分比就没法定义，但是Percentage change in number of的句子还是可以独立存在的。
下面这个话是google出来的：
"Percentage change in number of recorded incidents in 2002, compared with 2001"
这个话之后是一张表给出了这个变化的百分比。没有新的范围来定义前后两个百分比。我也想不出来一个合适的范围可以定义"recorded incidents"的百分比。
所以，没有新的范围引进，百分比的变化根本就不存在。推出应该是第二种理解。

这是我的理解，欢迎讨论。

作者: shim    时间: 2008-3-2 14:51

I just googled out an article published on http://jama.ama-assn.org/cgi/content/full/291/21/2600; please use Ctrl+F to find "percentage change in numbers of" as posted here below. You can also click the "table 3" to link to the relevant table. After carefully read through this article, I come to the conclusion that the latter definition should be right.

Trends and Percentage Change in Numbers of Underweight Children, 1990-2015
    

Table 3 presents estimates for 1990 and projections for 2015
        of the number of underweight children, and the relative percentage
        change with corresponding 95% CIs by geographical region. Worldwide,
        the number of underweight children was projected to decline
        from 163.8 million in 1990 to 113.4 million in 2015, a change
        of –31% (95% CI, –40% to –20%). In developed
        countries, the number was estimated to decline from 1.2 to 0.6
        million, a change of –54% (95% CI, –94% to 244).
        In developing regions, the number was forecasted to decline
        from 162.6 to 112.8 million, a change of –31% (95% CI,
        –40% to –20%).





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