BIZARRE results from wilcox.test()
The difference is so small as to be meaningless, and probably has to do with rounding error at the limits of machine precision. Really, why would you think this is either bizarre or important? Sarah
On Tue, Jun 14, 2011 at 4:57 PM, genecleaner <genecleaner at gmail.com> wrote:
I get these BIZARRE results from wilcox.test() When INCREASING the number of samples i get INCREASED p-values. When increasing the number of samples further, the p-values goes down again. This seems really bizarre! Can anyone explain why this is so?! Example:
w <- wilcox.test(c(1:40),(c(1:40)+100)) w$p.value
[1] 1.860340e-23
w <- wilcox.test(c(1:50),(c(1:50)+100)) w$p.value
[1] 7.066072e-18
w <- wilcox.test(c(1:60),(c(1:60)+100)) w$p.value
[1] 3.556571e-21
w <- wilcox.test(c(1:70),(c(1:70)+100)) w$p.value
[1] 1.817156e-24 Best regards, genecleaner (R version 2.11.1 (2010-05-31), Win7)
Sarah Goslee http://www.functionaldiversity.org