[R] model.tables

[Prof Brian D Ripley]

On Tue, 30 Nov 1999, spoon <spoon at hilbert.maths.utas.edu.au> wrote:

> Hi,
> 	Is this a bug or do I just not understand model.tables?
> 
> The problem is this: in the following, shouldn't the difference in
> means computed by model.tables be equal to the difference in the
> corresponding coefficients from coef(fit)?  That is, comparing diets
> d and e shouldn't
> 
> 34.71 - 41.53 = -6.82			# diff from model.tables
> 
> be equal to
> 
> -5.22500000  - 3.30000000 = -8.525	# diff from coef(fit)
> 
> Or am I just completely misinterpreting something basic?

Basically, yes. This is an incompletely replicated design, and d and e
occur on different litters.

The results are identical to the S-PLUS original. I think you are
probably looking for what dummy.coef gives you.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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