On 11-May-09 19:36:00, 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? > > Thanks > Anyuan
Yes, and you already looked at it but apparently did not recognise it! Either: qchisq(1-0.184, 2) ## (note "1-0.184", since 0.184 is the upper tail) # [1] 3.385639 Or: qchisq(0.184, 2, lower.tail=FALSE) ## Default for lower.tail is TRUE # [1] 3.385639 Enter ?qchisq for more informatio0n on this and related function. Ted. -------------------------------------------------------------------- E-Mail: (Ted Harding) <ted.hard...@manchester.ac.uk> Fax-to-email: +44 (0)870 094 0861 Date: 11-May-09 Time: 18:15:34 ------------------------------ XFMail ------------------------------ ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
