[R] Problem with multinom ?

[Marc Girondot]

>Dear Marc,
>
>I get the same results -- same coefficients, standard errors, and fitted
>probabilities -- from multinom() and glm(). It's true that the deviances
>differ, but they, I believe, are defined only up to an additive constant:
>
>>  predict(dt.b, type="response")
>         1         2         3
>0.4524946 0.5032227 0.5538845
>
>>  predict(dt.m, type="probs")
>         1         2         3         4         5         6
>0.4524948 0.4524948 0.5032229 0.5032229 0.5538846 0.5538846
>
>These fitted probabilities *are* correct: Since the members of each pair
>(1,2), (3,4), and (5,6) have identical values of factor they are identical
>fitted probabilities.

I expected rather to obtain (note 1- before some terms):
>     1         2         3         4         5         6
0.4524948 1-0.4524948 0.5032229 1-0.5032229 0.5538846 1-0.5538846

...

Marc
-- 

__________________________________________________________
Marc Girondot, Pr
Laboratoire Ecologie, Systématique et Evolution
Equipe de Conservation des Populations et des Communautés
CNRS, ENGREF et Université Paris-Sud 11 , UMR 8079
Bâtiment 362
91405 Orsay Cedex, France

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