R help - Jan 2005 - Wilcoxon test for mixed design (between-within subjects)

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)?

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.

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

Thank you for the consideration,

Regards,

Marco

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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