From: Peter Dalgaard <p.dalgaard_at_biostat.ku.dk>

Date: Tue 30 Aug 2005 - 23:46:44 EST

Date: Tue 30 Aug 2005 - 23:46:44 EST

torsten@hothorn.de writes:

> > Nice to see that the old code made sense.

*>
**> Nice to see that the new code is working correctly :-)
**>
**> > A bit surprising that it
**> > gives _exactly_ the same result as the blockwise ranking in coin...
**>
**> why? Without ties, the conditional and unconditional versions of the tests
**> should have exactly the same result.
*

Oh, just that there are a number of little things that could have been done in slightly different but asymptotically equivalent ways. The scale factor for the within-block ranks e.g.

> > Perhaps introduce some ties? (round(y,1) is usually effective).

*> >
**>
**> this should generate differences, yes.
**>
**> > The trend test is easily fixed: just spell "t value" without capital V
**> > as we do nowadays. This gives
**> >
**> >
**> > > SKruskal.test(y ~ x | b, data = mydf, trend = TRUE)
**> >
**> > Kruskal-Wallis stratified rank sum trend test
**> >
**> > data: y , group: x , strata: b , trend: as.numeric(group)
**> > Z = -0.1624, df = 1, p-value = 0.871
**> >
**> > > SKruskal.test(y ~ x | b, data = mydf, trend = 1:3)
**> >
**> > Kruskal-Wallis stratified rank sum trend test
**> >
**> > data: y , group: x , strata: b , trend: 1 2 3
**> > Z = -0.1624, df = 1, p-value = 0.871
**> >
**> > (The df=1 is a bit misleading in this case...)
**> >
**>
**> maybe report 0.1624^2 = 0.0264 as test statistic (same as with teststat
**> = "quad" in `coin')?
*

Yes, but there was a point in getting a signed statistic. Otherwise, I might as well have reused the code that used the SSD from the anova table.

-- 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@biostat.ku.dk) FAX: (+45) 35327907 ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.htmlReceived on Tue Aug 30 23:51:57 2005

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