[R] ANOVA procedure on the sufficient statistics

[Peter Dalgaard]

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   
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