求助 OG 112

月明夕

In tests for pironoma, a serious disease, a false positive result indicates that people have pironoma when, in fact, they do not; a false negative result indicates that people do not have pironoma when, in fact, they do. To detect pironoma most accurately, physicians should use the laboratory test that has the lowest proportion of false positive results.

which of following, if true, gives the most support to the recommendation above?

A .The accepted treatment for pironoma does not have damaginh side effects.

B. The laboratory test that has the lowest proportion of false positive results causes the same minor side effects as do the other laboratory tests used to detect pironoma.

C.In treating pironoma patients, it is essential to bigin treatment as early as possible, since ever a week of delay can result in loss of life.

D. The proportion of inconclusive test results is equal for all laboratory tests rsed to detect pironoma.

E.  All laboratory tests to detect pironoma have the same proportion of false negative results.

这道题的答案是E . 虽然看了OG的解释但还是想不明白.希望得到大家的帮助,谢了!

julianfl

影响检测正确率的因素有两个，一个是fase positive results， 一个是false negative results

原文说最正确的情况，是当fase positive results最少的情况。：）

不能忽略另一个影响因素，所以加一个support，说false negative results在任何测试出现的比例都一样。消除差异影响。：）

关于这道题目的讨论帖：http://forum.chasedream.com/dispbbs.asp?boardID=24&ID=90184&page=1

[此贴子已经被作者于2007-4-20 0:25:50编辑过]

月明夕

消除差异？误诊为阴性的比例是一样的，难道就可以加强误诊为阳性的比例是最小的？

有点晕……请多见谅!还请高人指点！不胜感谢＾－＾

julianfl

这么说吧，导致C的两个因素为A和B

如果A是一个常量，则C的变化仅随B的变化而变化。

误诊为阴性的比例是一样的其实就是让影响检测正确率的两个因素之一为常量：） 那么另一个误诊为阳性的比例和检测正确率就成反比，误诊为阳性的比例最低，检测正确率最高。

月明夕

呵呵 这个解释很有意思 很清楚 谢谢啦