R implementations of Student's t, chi-squared, F, and beta distributions all support noncentrality parameters. There is often a need (for example in sample size problems) to invert the cdf to obtain the noncentrality parameter given the quantile, instead of to obtain the quantile given the noncentrality (as the q... functions do). For example, in SAS, these functions are called TNONCT, CNONCT, and FNONCT. I believe that 2.7.0 was the current version when I submitted this on 27 May, 2008. If it has been subsequently addressed, I can find no mention of it either in the 2.7.2 Reference Manual or in today's https://svn.r-project.org/R/trunk/NEWS Jerry Uwe Ligges <ligges at statistik.tu-dortmund.de> wrote
Jerry.Lewis at biogenidec.com wrote:
Full_Name: Jerry W. Lewis Version: 2.7.0 OS: Windows XP Professional Submission from: (NULL) (198.180.131.16) If you are saying that there is no need to solve for the noncentrality parameter, please justify this amazing assertion.
- He? What noncentrality are you talking about? - You are reporting a bug with an outdated version of R. - You have not followed the guide on how to report bugs in R. Uwe Ligges
If you are saying that this need is already adequately addressed in R,
then
please enlighten me.