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Re: GLM Saturated Model Question
Posted:
Apr 1, 2013 1:38 AM


On Sun, 31 Mar 2013 12:44:09 0700 (PDT), SChapman <sumanthcp@googlemail.com> wrote:
> > >In the chapter on Analysis of Deviance on Generalized Linear Models I came across 'Saturated Model'  a model that includes as many parameters as the number of observations. > >1) I am having difficulty visualising Saturated model. Can someone please give me the Saturated model in terms of Yi, X1i, X2i etc? > >2) Since I am unable to visualise the saturated model, I can't appreciate the fact that the for the saturated model the fitted value is in fact the actual response value.
I don't think of "staturated model" in any ANOVA context.
Where I have encountered the term is in multidimensional, loglinear model building. In that case, the number of parameters is equal to the number of d.f. rather than the number of observations.
For instance, a 2x2x2 table has 7 d.f. There are 3 main effects (means), 3 interactions of two terms, and one 3way interaction in the saturated model. The use of the saturated model is for computing the deviance from the lessfull model, instead of just saying "from zero". I guess it seems more proper to do it that way.
 Rich Ulrich



