[R] Fisher test problem
Viju Moses
vijumoses at gmail.com
Sat Mar 21 20:17:41 CET 2009
Hi, I noted a discrepancy between R and openepi when I ran a fisher test
with the same matrix. In R:
> a=matrix(c(1,2,6,17), nrow=2)
> a
[,1] [,2]
[1,] 1 6
[2,] 2 17
> fisher.test(a, conf.int=T)
Fisher's Exact Test for Count Data
data: a
p-value = 1
alternative hypothesis: true odds ratio is not equal to 1
95 percent confidence interval:
0.02061498 31.73691924
sample estimates:
odds ratio
1.396646
But in openepi the P value is 1.25. (In another instance too for other
sets of data, I had got a p value of 1 in 3 instances for a prop.test
when I got 3 other answers on a friend's stata software with the same
data. )
I'm using R on Ubuntu Intrepid. Is there anything I'm doing wrong? Any
other packages I have to install?
Thanks in advance
Viju Moses
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