On 2/7/2008 12:00 PM, jing hua zhao wrote: > Dear R list, > > I calculated a two-sided p values according to 2*(1-pnorm(8.104474)), which > gives 4.440892e-16. However, it appears to be 5.30E-16 by a colleague and > 5.2974E-16 from SAS. I tried to get around with mvtnorm package but it turns > out to be using pnorm for univariate case. I should have missed some earlier > discussions, but for the moment is there any short answer for a higher > precision?
You are taking the difference between two numbers, 1 and a number that is almost equal to 1. Don't do that, it results in a catastrophic loss of precision. Evaluate the upper tail probability directly: > 2*(pnorm(8.104474, lower=FALSE)) [1] 5.29742e-16 Duncan Murdoch Somehow these days, statistical geneticists are infatuated with such tiny p values! > > Many thanks in advance, > > > Jing Hua > > _________________________________________________________________ > Telly addicts unite! > > [[alternative HTML version deleted]] > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
