[R] Multinomial models

[Prof Brian Ripley]

On Thu, 21 Jun 2007, nicole baerg wrote:

> Hello,
>
> I am VERY new to R (one week) and I am trying to run a multinomial logit model.
> The model I am using is
>
>> model1 <- multinom(Y ~ X1 + X2 + , ..., Xn)
>
> if I put in
>
>> summary(model1)
>
> I get
>
> #Error in function (classes, fdef, mtable)  :
>        unable to find an inherited method for function "fitted", for
> signature "multinom"

You have some other package attached (you are using 'nnet' without mention 
or credit) that has broken summary() (the correct summary method does not 
use fitted()).  The R posting guide asks for the output of sessionInfo(), 
and that would have helped us here. All I can tell is that the culprit is 
an S4-using package.

Try again with only the smallest possible set of packages attached.

> and if I put in
>
>> coef(model1)
>
> I get the coefficients. I would like, however, to get the
> coefficients, estimates, Std Erros and t-Ratios and/or z or P>[z]
>
> Also can you change the speficiation of the base category without recoding?

?contr.treatment
?relevel

> Thanks.
>
> Nicole
>
> ______________________________________________
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

PLEASE do

-- 
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 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595