Thank you David I think that makes sense.

As a side note I have been doing some work with fish abundance in aquaria. The TRUE column is the actual amount of fish in the tank, so a questionable practice but a valid one??

Thanks again, 
Stephen
On 25 Nov 2012, at 20:41, David Winsemius [via R] wrote:

> 
> On Nov 25, 2012, at 4:55 AM, sm2284 wrote: 
> 
> > Dear R-ers, 
> > 
> > I am currently running some Wilcoxon tests in R-64. 
> > 
> > How do I find the degrees of freedom in the output I am receiving? 
> > 
> >> wilcox.test(good$TRUE, good$x4a, paired=FALSE) 
> > 
> > Wilcoxon rank sum test with continuity correction 
> > 
> > data:  good$TRUE and good$x4a 
> > W = 2455, p-value < 2.2e-16 
> > alternative hypothesis: true location shift is not equal to 0 
> >
> When using wilcox.test with two samples, the function passes some   
> version of the Rank-Sum statistic W to the pwilcox function followed   
> by the lengths of the two vectors. So I suppose you could say the   
> sample sizes are the "degrees of freedom". Reasoning informally I   
> would think the smaller of those lengths would be the most important   
> in determining stability of the inference. 
> 
> BTW, methinks it a very questionable practice to name a column 'TRUE'. 
> 
> -- 
> David Winsemius, MD 
> Alameda, CA, USA 
> 
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Stephen James McKelvie
sjmckelvie@gmail.com







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University of St Andrews, 
sm2284@st-andrews.ac.uk
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