[R] Dunnett's test

Peter Dalgaard BSA p.dalgaard at biostat.ku.dk
Tue Oct 23 01:03:07 CEST 2001

kjetil halvorsen <kjetilh at umsanet.edu.bo> writes:

> > help.search("dunnett")
> No help files found with alias or title matching `dunnett'
> so it seems like nobody have implemented this.
> for how to build it in R, see the " writing R extensions manual", and
> look in ctest for examples of how to use 
> "htest". For writing dunnett.test, it will be a good idea to return the
> result as a list with class "htest". Then the printing of the result
> will be done
> automatically.
> Kjetil Halvorsen

The real obstacle would seem to be the distribution of the many-one
t-statistic. This doesn't seem to be available from any of the
standard subroutine sources (apstat and toms). Miller's book cites the
tables from a 1964 paper by Dunnett - I browsed through it earlier
today and it seemed that the density can be calculated explicitly, but
you need numerical integration to get the CDF. Anyone have a handful
of spare evenings to code this up?

   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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