Re: [R] p-value > 1 in fisher.test()

From: Ted Harding <Ted.Harding_at_nessie.mcc.ac.uk>
Date: Sat 04 Jun 2005 - 06:45:24 EST


On 03-Jun-05 Peter Dalgaard wrote:
> "Yi-Xiong Zhou" <yzhou@sdsc.edu> writes:
>

>> The following contingency table generates p-value > 1 from
>> fisher.test()
>> 
>>  
>> 
>> ff = c(0,10,250,5000); dim(ff) = c(2,2); fhisher.test(ff)$p.value

>
> On this system (PIII, Fedora Core 3):
>
>> ff = c(0,10,250,5000); dim(ff) = c(2,2); fisher.test(ff)$p.value -1

> [1] 1.384892e-12
>
> Is that interesting?

And on mine

(A: PII, Red Had 9, R-1.8.0):

 ff <- c(0,10,250,5000); dim(ff) <- c(2,2);

 1-fisher.test(ff)$p.value
 [1] 1.268219e-11

(B: PIII, SuSE 7.2, R-2.1.0beta):

 ff <- c(0,10,250,5000); dim(ff) <- c(2,2);

 1-fisher.test(ff)$p.value
 [1] -1.384892e-12

Peter, I'm not sure which is the more interesting!

Best wishes,
Ted.



E-Mail: (Ted Harding) <Ted.Harding@nessie.mcc.ac.uk> Fax-to-email: +44 (0)870 094 0861
Date: 03-Jun-05                                       Time: 21:45:13
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