[R] Wilcoxon test for mixed design (between-within subjects)

[Christoph Buser]

Hallo Marco

Marco Chiarandini writes:
 > Hallo,
 > 
 > is there any extension of the pairwise Wilcoxon test to a dependent
 > samples layout with replicates (or, in other terms, a one-way layout
 > with blocking and replicates)?
 > 

There is always the possibility to summarize the replicates and
then calculate a common pairwise Wilcoxon test.


 > The Wilcoxon method with matched pairs works for the case of dependent
 > samples with one observation per block, while the Mann-Whitney test
 > works for independent samples, thus one single block and replicated
 > observations. Is there a method which mixes this two cases considering a
 > depedent sample design in which each block has more than one
 > observation? I know it exists a Friedman test for this case but in the
 > Friedman test ranks are constructed considering all subjects jointly,
 > while in Wilcoxon only the pair of subject currently considered are
 > ranked, thus resulting in a more powerful test.
 > 

The Friedman test calculates the ranks inside of the blocks, for
each block separately and is not considering all subjects
jointly.
In R implemented is the case with unreplicated blocked data, so
this doesn't help you. 

 > If no such method exists in R, I am anyway intersted in possible
 > references.

Look at:

     Myles Hollander & Douglas A. Wolfe (1999), _Nonparametric
     statistical methods_. New York: John Wiley & Sons. 

There you find the generalization of the replicated case, but
you have to implement it.

Regards,

Christoph Buser

--------------------------------------------------------------
Christoph Buser <buser at stat.math.ethz.ch>
Seminar fuer Statistik, LEO C11
ETH (Federal Inst. Technology)	8092 Zurich	 SWITZERLAND
phone: x-41-1-632-5414		fax: 632-1228
http://stat.ethz.ch/~buser/
--------------------------------------------------------------



 > Thank you for the consideration,
 > 
 > Regards,
 > 
 > Marco
 > 
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