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

[Marco Chiarandini]

Hallo Christoph,


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


mmmh, in this case I prefer the Friedman test, I would like not to loose
any data.


> The Friedman test calculates the ranks inside of the blocks, for
> each block separately and is not considering all subjects
> jointly.


true, but it considers all the treatments together, while Wilcoxon works
per pairs of treatments within the blocks.


> 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.


I already implemented the Friedman test for the replicated case although
taken from Conover 1999 _Practical non parametric statistics_. I hope it
is the same. My interest in a Wilcoxon procedure is due to the fact that
according to Hsu 1996 _Multiple comparisons_ the Friedman test is not
recommended for multiple comparisons becasue it has been shown that it
is not a confident method (the actual alpha value is greater).


Regards,


Marco



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Marco Chiarandini, Fachgebiet Intellektik, Fachbereich Informatik,
Technische Universität Darmstadt, Hochschulstraße 10,
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