charles78 wrote:> I have a stupid question on how to get the real p-values for wilcox.test
and
> correlation. the minmun can be reached is 2.2E-16 using the R version
> 2.6.2. I do not think it is the R version causing this but other issues.
>
> Any help is highly appreciated.
>
> Charles
It's mainly a printing issue (and to some extent historical, because
small p-values in the upper tail were generated by subtraction and could
underflow if < 2.2e-16):
> wilcox.test(1:100,101:200)
Wilcoxon rank sum test with continuity correction
data: 1:100 and 101:200
W = 0, p-value < 2.2e-16
alternative hypothesis: true location shift is not equal to 0
> wilcox.test(1:100,101:200)$p.value
[1] 2.562144e-34
--
O__ ---- Peter Dalgaard ?ster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907