[R] Pearson corelation and p-value for matrix

[John Fox]

Dear Dren,

How about the following?

 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
Canada L8S 4M4
905-525-9140x23604
http://socserv.mcmaster.ca/jfox 
-------------------------------- 

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Dren Scott
> Sent: Friday, April 15, 2005 4:33 PM
> To: r-help at 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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