[R] BIZARRE results from wilcox.test()

[Sarah Goslee]

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