[R] power 2x3 exact test
Duncan Murdoch
murdoch at stats.uwo.ca
Thu May 10 00:00:27 CEST 2007
On 09/05/2007 5:11 PM, Bingshan Li wrote:
> Hi, all,
>
> I am wondering if there is an algorithm for calculating power of 2x3
> table using Fisher exact test. There is one (algorithm 280) for 2x2
> Fisher exact test but I couldn't find one for 2x3 table. If we are
> not lucky enough to have one, is there any other way to calculate
> exact power of 2x3 table? The reason why I want exact power is
> because some cells are assumed to be very small and chi square
> approximation is not valid.
I think there are lots of possible alternatives to the null in a 2x3
table, so you may have trouble finding a single answer to this question.
But assuming you have one in mind, I'd suggest doing a Monte Carlo
power calculation: simulate a few thousand tables from the alternative
distribution, and see what the distribution of p-values looks like.
Duncan Murdoch
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