[R] ANOVA procedure on the sufficient statistics
Peter Dalgaard
p.dalgaard at biostat.ku.dk
Thu Feb 19 21:41:32 CET 2004
Duncan Murdoch <dmurdoch at pair.com> writes:
> On Thu, 19 Feb 2004 08:45:01 -0500, Michael Friendly
> <friendly at yorku.ca> wrote :
> >That will generate only approximately the same means and MSE, however.
> >
> >Larsen's procedure generates a weighted data set that gives the same
> >ANOVA table
> >as the raw data, but requires that the weight= argument be used in aov().
> >(weights are not supported in all related functions)
>
> Are you sure about that? I think the call to "scale()" makes them
> come out identical.
>
> In fact, the call to rnorm() is unnecessary; it would work just as
> well with
>
> y <- cell.mean + cell.sd * scale(1:cell.count)
>
> (unless I'm missing something...)
I don't think so, but residual plots etc. look better with the rnorm()
variant...
--
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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