# RE: [R] Pearson corelation and p-value for matrix

From: John Fox <jfox_at_mcmaster.ca>
Date: Sat 16 Apr 2005 - 08:26:07 EST

Dear Dren,

cor.pvalues <- function(X){

nc <- ncol(X)
res <- matrix(0, nc, nc)
for (i in 2:nc){

```        for (j in 1:(i - 1)){
res[i, j] <- res[j, i] <- cor.test(X[,i], X[,j])\$p.value
}
}
```

res
}

What one then does with all of those non-independent test is another question, I guess.

I hope this helps,
John

John Fox
Department of Sociology
McMaster University
Hamilton, Ontario
905-525-9140x23604
http://socserv.mcmaster.ca/jfox

> -----Original Message-----
> From: r-help-bounces@stat.math.ethz.ch
> [mailto:r-help-bounces@stat.math.ethz.ch] On Behalf Of Dren Scott
> Sent: Friday, April 15, 2005 4:33 PM
> To: r-help@stat.math.ethz.ch
> Subject: [R] Pearson corelation and p-value for matrix
>
> Hi,
>
> I was trying to evaluate the pearson correlation and the
> p-values for an nxm matrix, where each row represents a
> vector. One way to do it would be to iterate through each
> row, and find its correlation value( and the p-value) with
> respect to the other rows. Is there some function by which I
> can use the matrix as input? Ideally, the output would be an
> nxn matrix, containing the p-values between the respective vectors.
>
> I have tried cor.test for the iterations, but couldn't find a
> function that would take the matrix as input.
>
> Thanks for the help.
>
> Dren
>
>
>
>
> ---------------------------------
>
>
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