[R] suggestion for proportions

csrabak cesar.rabak at gmail.com
Thu Sep 8 02:31:13 CEST 2011


Em 7/9/2011 16:53, array chip escreveu:
> Hi all, thanks very much for sharing your thoughts. and sorry for my describing the problem not clearly, my fault.
>
> My data is paired, that is 2 different diagnostic tests were performed on the same individuals. Each individual will have a test results from each of the 2 tests. Then in the end, 2 accuracy rates were calculated for the 2 tests. And I want to test if there is a significant difference in the accuracy (proportion) between the 2 tests. My understanding is that prop.test() is appropriate for 2 independent proportions,  whereas in my situation, the 2 proportions are not independent calculated from "paired" data, right?
>
> the data would look like:
>
> pid   test1    test2
> p1      1         0
> p2      1         1
> p3      0         1
> :
> :
>
> 1=test is correct; 0=not correct
>
> from the data above, we can calculate accuracy for test1 and test2, then to compare....
>
>
> So mcnemar.test() is good for that, right?
>
> Thanks
>
John,

 From above clarifying I suggest you consider the use of kappa test. For 
a list of possible ways of doing it in R try: 
RSiteSearch("kappa",restrict="functions")

HTH

--
Cesar Rabak



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