R help - Nov 2005 - effect sizes for Wilcoxon tests

Hello,

I use t.test for normal distributed and wilcox.test for non-normal
distributed samples.

It is easy to write a function for t.test that calculates the effect
size, because all parts of the formula are available from the t.test
result: r = sqrt(t*t / (t*t + df))

However, for Wilcoxon tests, the formula for effect sizes is:
r = Z / sqrt(N)

I wonder how I can calculate the Z-score in R for a Wilcoxon test.

BTW, would it be correct to name "wilcox.test(..., paired=F)" a
"Mann-Whitney test" in a report?  If I understand the documentation
(?wilcox.test) correctly, R does actually not use Mann-Whitney, but the
equivalent Wilcoxon test.

Thanks for clarification.
Claus

On Mon, 14 Nov 2005, Claus Atzenbeck wrote:
> However, for Wilcoxon tests, the formula for effect sizes is:
> r = Z / sqrt(N)
>
> I wonder how I can calculate the Z-score in R for a Wilcoxon test.
Does anyone know how to calculate effect sizes for Wilcoxon tests as
SPSS can do? I wonder if it would be very difficult to do so with R.

Thanks...
Claus