[R] Friedman test for replicated blocked data

Marco Chiarandini machud at intellektik.informatik.tu-darmstadt.de
Mon Dec 13 18:20:51 CET 2004


I would need to extend the Friedman test to a replicated
design. Currently the function: friedman.test(y, ...) only works for
unreplicated designs.

I found in Conover 1999 "Practical Nonparamteric statistics" an
extension of the formula to my case.

Nevertheless, other sources, like Sheskin 2000 "Parametric and
Nonparametric statistical Procedures" and Daniel 1990 "Applied
nonparametric statistics" give a different formula from that of Conover
in the unreplicated case. Since they do not provide the extension of
this formula to the replicated case I would like to know if someone
could give me a reference where I could find such extension. The formula
is indeed very simple:

F= z \sqrt{bk(k+1)/6}

where z is a quantile from the normal distribution, b the number of
blocks and k the number of treatments.

Unfortunately, the sources cited do not provide indications from where
the formula comes from.

Thank you for consideration,



Marco Chiarandini,
Technische Universitaet Darmstadt

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