[R] read table for Fisher Exact

[Shi, Tao]

Hi Prof. Harrell,

Could you please elaborate on why chi-square test is more appropriate in this case?  Thank you very much!

...Tao





----- Original Message ----
> From: Frank E Harrell Jr <f.harrell at vanderbilt.edu>
> To: r-help at r-project.org
> Sent: Thu, May 13, 2010 5:35:07 AM
> Subject: Re: [R] read table for Fisher Exact
> 
> On 05/12/2010 03:31 PM, visser wrote:
>
> i have 2 groups i want to 
> compare: group A and group B
> each group contains let's say 20 
> patients
> i want to perform a Fisher Exact test on genotype 
> distribution
> so, see if there is a sign diff in genotpe 
> frequency/distribution (#AA, #AB,
> #BB) between group A and B
> not 
> for 1, but for 1000 different genes
>
> my question: how should i 
> build my table so i can do:
>
> test<- 
> read.table("table1.txt")
> fisher.test(test)
>
> i know a lot 
> is still missing in the syntax, but i do not know what. any
> help would 
> be soo much appreciated!!

Note that in this case, Fisher's exact test has 
> a good chance of being 
less accurate than an approximate Pearson chi-square 
> test.

-- 
Frank E Harrell Jr   Professor and Chairman  
>       School of Medicine
          
>             Department of Biostatistics  
> Vanderbilt 
> University

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