[R] Previously attainable fisher's exact test

[(Ted Harding)]

On 13-Apr-11 17:40:53, Jim Silverton wrote:
> I have a matrix say,
> 
> 1  4
> 23  30
> 
> and I want to find the previously attainable fisher's exact test
> p-value. Is there a way to do this in R?
> -- 
> Thanks,
> Jim.

I do not understand what you mean by "previously attainable".

As far as that particular matrix is concerned, the fisher.test()
function will yield its exact Fisher P-value:

  M <- matrix(c(1, 4, 23, 30), byrow=TRUE, nrow=2)
  M
  #      [,1] [,2]
  # [1,]    1    4
  # [2,]   23   30
  fisher.test(M)
  #         Fisher's Exact Test for Count Data
  # data:  M 
  # p-value = 0.3918
  # alternative hypothesis: true odds ratio is not equal to 1 
  # 95 percent confidence interval:
  #  0.006355278 3.653391412 
  # sample estimates:
  # odds ratio 
  #  0.3316483

So the P-value is 0.3918 (as attained now, and as attainable
at any time previously if you had done the above ... !).

Ted.

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Date: 14-Apr-11                                       Time: 00:28:59
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