Thanks Michael I assumed as much but we know what that did. Thanks again.
Elliott -----Original Message----- From: R. Michael Weylandt [mailto:michael.weyla...@gmail.com] Sent: 15 March 2013 09:29 To: elliott harrison Cc: r-help@r-project.org Subject: Re: [R] phyper returning zero On Fri, Mar 15, 2013 at 8:52 AM, elliott harrison <e.harri...@epistem.co.uk> wrote: > Hi, > I am attempting to use phyper to test the significance of two overlapping > lists. I keep getting a zero and wondered if that was determining > non-significance of my overlap or a p-value too small to calculate? > > overlap = 524 > lista = 2784 > totalpop = 54675 > listb = 1296 > > phyper(overlap, lista, totalpop, listb,lower.tail = FALSE, log.p=F) > [1] 0 If you set log.p = T, you see that the _log_ of the desired value is -800, so it's likely simply too small to fit in a IEEE double. In sort, for all and any practical purposes, your p-value is zero. Cheers, MW This message has been scanned for malware by Websense. www.websense.com ______________________________________________ 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.
