[R] anyone know how to calculate chi square value from P value?

[Duncan Murdoch]

On 5/11/2009 3:36 PM, Anyuan Guo wrote:
> Dear all,
>     I have P value of a list of markers. Now I need the chi square value 
> with degrees of freedom 2.
>     I noticed there are several Chisquare functions (dchisq, pchisq, 
> qchisq, and rchisq), but it seems all are not for my purpose.
>     In microsoft excel, there is a function CHINV to do this, such as 
> CHINV(0.184, 2) is 3.386, that means the chi square value for P value 
> 0.184, degree 2 is 3.386.
>     Does the R package has some function to do this?

qchisq(0.184, df=2, lower=FALSE)

Duncan Murdoch