[R] Does Chi Square test for R differ from S-Plus?

Prof Brian Ripley ripley at stats.ox.ac.uk
Tue Mar 23 10:12:38 CET 2004


Depends on the `GLM' model and what you mean by that (general linear 
model, generalized linear model?).  And by `Anova' (capitalized), for that 
matter.

S-PLUS (sic) does some inconsistent things with dispersion parameters in 
glm() fits, and it is likely that you are using the wrong test.  But P 
values that near one should arouse your suspicions.

Please read the R posting guide, and then tell us enough of what you did
so we can help you.  

On Tue, 23 Mar 2004, Ridwan Sala wrote:

> I tried to run a GLM model using S-Plus and R. The same model and data were 
> applied to the both packages. I got different results of  P(>|Chi|) for Anova, 
> between S-PLus and R. Other estimates values are the same. 
> 
> P(>|Chi|) for S-Plus:
> 0.99565 0.99682 0.04871 0.84597 1.00000 0.99999 1.00000 1.00000 1.00000 0.95834
> 
> P(>|Chi|) for R:
> 0.00000 0.00000 0.00000  0.00000 0.00000 0.00000 0.00350 0.26400 0.46800 0.0000
> 
> I used S-Plus 6.1 for windows, Profesional Edition release 1, and R 1.8.1.
> 
> Does anyone have any idea how this could happen? 

-- 
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




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