[Rd] small bug in ansari.test

Peter Dalgaard p.dalgaard at biostat.ku.dk
Thu Mar 29 23:05:30 CEST 2007

Thomas Friedrichsmeier <thomas.friedrichsmeier at ruhr-uni-bochum.de>

> On Thursday 29 March 2007 21:39, Thomas Friedrichsmeier wrote:
>> The help page for ansari.test() says (emphasis added):
>> 	By default (if exact is not specified), an exact p-value is computed if
>> both samples contain less than 50 finite values **and there are no ties**.
>> Otherwise, a normal approximation is used.
>> However, this does not appear to be the case in R 2.4.1 or R 2.5.0.
> Well, to be precise, the exact p-value really isn't computed in this case, but 
> there's still the warning, as though exact=TRUE had been specified, which I 
> don't believe is intended.


Those samples contain less than 50 values but there are ties, so you
get the normal approximation with a warning.  If you specify
exact=FALSE, you get the same result without the warning. 

Where's the bug??

   O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
  c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
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