[R] wilcox.test and ties

[kjetil halvorsen]

"Swanepoel, Christiaan Edward" wrote:
> 
> Hello,
> 
> when performing the wilcox.test on a sample (n=100) with the following frequency distribution:
> Value   |       Frequency
> ----------------------------------------
> 0       |       10
> 0.1     |       88
> 1       |       1
> 2.6     |       1
> 
> I get the following error message:
> 
> Error in uniroot(wdiff, c(mumin, mumax), tol = 1e-04, zq = qnorm(alpha/2,  :
>         f() values at end points not of opposite sign
> 
> The error only occurs when I specify that the confidence interval should be computed.
> 
> Could anybody suggest how I can compute the confidence interval for this sample? Is the problem connected with the large number of ties and if so, how can I handle these ties?

You could look inti the package exactRankTests.

Kjetil Halvorsen

> 
> Thanks in advance.
> 
> Regards
> Chris
> 
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