[R] F tests for glms with binomial error

[tr217@cam.ac.uk]

Hi, can anyone help with this:

I am trying to analyse some data in the form of proportions with the glm 
function in R and S-plus.  When comparing different models with an F test, 
I get different results from R and S-plus.  Here's an example (there are 
two factors and an interaction in the full model 
"glm1<-glm(resp~time*set,family=binomial"):

In R, entering "anova(glm1)" I get this:

		DF	Deviance	Resid. DF	Resid. Deviance	F		Pr(>F)
NULL					51		213.13		
time		1	1.403		50		211.727		1.4032	0.23618
set		6	98.527	44		113.2			16.4211	<2e-16***
time:set    6	13.659	38		99.541		2.2765	0.03368* 


But in S-plus, I get this:

		DF	Deviance	Resid. DF	Resid. Deviance	F		Pr(>F)
NULL					51		213.13		
time		1	1.403		50		211.727		0.6749	0.4165
set		6	98.527	44		113.2			7.8986	0.000015***
time:set    6	13.659	38		99.541		1.0950	0.3831

Everything is the same, except for the F ratios.  Does anyone know why (as 
you can see it makes quite a difference to the significance of the 
interaction term)?

Thanks,

Tom Reader.    
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