Søren Faurby <soren.faurby <at> biology.au.dk> writes: > > In an effort to select the most appropriate number of clusters in a > mixture analysis I am comparing the expected and actual membership of > individuals in various clusters using the Fisher?s exact test. I aim > for the model with the lowest possible p-value, but I frequently get > p-values below 2.2e-16 and therefore does not get exact p-values with > standard Fisher?s exact tests in R. >
The p<2.2e-16 is a printing issue, not a precision issue. > ff = fisher.test(dat3, workspace=30000000) > ff Fisher's Exact Test for Count Data data: dat3 p-value < 2.2e-16 alternative hypothesis: two.sided > str(ff) List of 4 $ p.value : num 5.88e-58 $ alternative: chr "two.sided" $ method : chr "Fisher's Exact Test for Count Data" $ data.name : chr "dat3" - attr(*, "class")= chr "htest" So just use ff$p.value ______________________________________________ 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.