[R] fisher exact for > 2x2 table

Thomas Lumley tlumley at uw.edu
Thu Apr 28 22:12:21 CEST 2011


On Fri, Apr 29, 2011 at 8:01 AM, Mike Miller <mbmiller+l at gmail.com> wrote:
> On Thu, 28 Apr 2011, viostorm wrote:
>
>> I'm using fisher.exact on a 4x2 table and it seems to work.
>>
>> Does anyone know exactly what is going on?  I thought fisher.exact is only
>> for 2x2 tables.
>
>
> You were wrong.  I'm sure there's nothing wrong with the program.  You will
> find that with bigger tables and larger sample sizes the computational cost
> becomes quite enormous.

In fact, with large tables, roundoff error becomes significant before
computational cost becomes prohibitive.

     -thomas

-- 
Thomas Lumley
Professor of Biostatistics
University of Auckland



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