R help - Jun 2008 - omnibus LR in multinomial model

If one estimates a model using multinom, is it possible to perform the 
omnibus LR test ( the analogue to omnibus F in linear models )  using 
the output
from multinom ? The residual deviance is there but I was hoping I could 
somehow pull out the deviance based on just using an intercept ?
Sample code  is below from the CAR book but I wasn't sure how to do it 
based on that example. Thanks for any insights.


library(car)
library(nnet)

attach(Womenlf)

participation <- ordered(partic, levels=c('not.work',
'parttime',
'fulltime'))
print(participation)

mod.multinom <- multinom(participation ~ hincome + children)
print(mod.multinom)
print(str(mod.multinom))

Is this what you were trying to do?
See intercept model and anova below.

HTH

Steve McKinney

> -----Original Message-----
> From: r-help-bounces at r-project.org
[mailto:r-help-bounces at r-project.org]
> On Behalf Of markleeds at verizon.net
> Sent: Friday, June 20, 2008 3:47 PM
> To: r-help at stat.math.ethz.ch
> Subject: [R] omnibus LR in multinomial model
> 
> If one estimates a model using multinom, is it possible to perform the
> omnibus LR test ( the analogue to omnibus F in linear models )  using
> the output
> from multinom ? The residual deviance is there but I was hoping I
could
> somehow pull out the deviance based on just using an intercept ?
> Sample code  is below from the CAR book but I wasn't sure how to do it
> based on that example. Thanks for any insights.
> 
> 
> library(car)
> library(nnet)
> 
> attach(Womenlf)
> 
> participation <- ordered(partic, levels=c('not.work',
'parttime',
> 'fulltime'))
> print(participation)
> 
> mod.multinom <- multinom(participation ~ hincome + children)
> print(mod.multinom)
> print(str(mod.multinom))
> mod.multinom0 <- multinom(participation ~ 1)
# weights:  6 (2 variable)
initial  value 288.935032 
final  value 250.246281 
converged
> anova(mod.multinom, mod.multinom0)
               Model Resid. df Resid. Dev   Test    Df LR stat.
Pr(Chi)
1                  1       524   500.4926           NA       NA
NA
2 hincome + children       520   422.8819 1 vs 2     4 77.61064
5.551115e-16
>
> 
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