[R] 2 x 3 Probability under the null

[Duncan Murdoch]

On 11-10-27 12:09 AM, Jim Silverton wrote:
> I have a 2 x 3 matrix called snp and I want to compute the following
> probability:
>
> choose(sum(snp[,1]), snp[1,1]) * choose(sum(snp[,2]), snp[1,2]) *
> choose(sum(snp[,3]), snp[1,3])/choose(sum(snp), sum(snp[1,]))
>
> but I keep getting Infs and NaNs. Is there a function that can do this in R?
>
>
>

Work in the log scale.  You're probably getting overflows.  lchoose() 
calculates the log of choose().

Duncan Murdoch