求教OG-87-置疑答案和自己

myfang

以下是引用kinci在2005-8-19 9:59:00的发言：

这道题目可以这样看：

只有两种错误：false negative 和false positive

写成公式：总的错误 =“false negative ”+“false  positive”

如果false negative都一样，那么错误率只和false  positive有关，那么false  positive越低整个错误率就越低，准确率就越高了。

我觉得这道题的理解可以改进为:

Test 1:FP1+FN1=F1(错误率1)

Test 2: FP2+FN2=F2

Test 3: FP3+FN3=F3

......

要使得F最低,FN应该如何,可以得出FP最低?

答案:FN不变,或者FP1最低的同时FN1也最低.

myfang

以下是引用wicup在2007-2-9 10:08:00的发言：

E is the right answer. The reason is:

To test the disease, there are only two options: false positive tests (X) and false negative tests (Y). If all tests have the same proportion of false negative results ( X is constant), the proportion of false positives is the only determinig variable in the choice of the most accurate test (Y is the only variable).

Choice A and C are irrelevant because the question is about the "testing" for the disease, not the "treat

To test the disease, perhaps there are many results, but only two false results as options: false positive tests (X) and false negative tests (Y)

ada3063

我觉得这道题应该归到assumption里

zuozuox

以下是引用kinci在2005-8-19 9:59:00的发言：

这道题目可以这样看：

只有两种错误：false negative 和false positive

写成公式：总的错误 =“false negative ”+“false  positive”

如果false negative都一样，那么错误率只和false  positive有关，那么false  positive越低整个错误率就越低，准确率就越高了。