[Rd] help page for anova.glm/variation between S-PLUS and R
Mon Jan 27 19:27:03 2003
OK, then, what about adding a note to section 3.3.3 (Other differences
between R and S-PLUS) of the R FAQ ? I just want to minimize confusion
for people crossing over -- at least point to the fact that S-PLUS handles
On Mon, 27 Jan 2003 firstname.lastname@example.org wrote:
> Not really!
> I don't think it is our job to describe the inconsistencies of S-PLUS,
> especially since that might change from version to version. It would be
> really messy, as S-PLUS ignores the scale for the Chisq test (which seems
> perverse), and lacks the dispersion argument.
> On Mon, 27 Jan 2003, Ben Bolker wrote:
> > When using test="F" in stat.anova() / anova.glm(), R uses the assumed
> > dispersion parameter for the specified family (e.g. scale=1 for binomial),
> > while S-PLUS automatically uses the estimated dispersion parameter
> > (residual deviance/residual df). I think there are good reasons for the
> > behavior in R -- it fits with the "you get what you actually asked for"
> > philosophy -- and there are hints in the documentation (anova.glm(): "for
> > [models] with dispersion estimated by moments ... the F test is most
> > appropriate"; family/binomial(): "The behaviour of S-PLUS is closer to the
> > quasi- variants").
> > Would R-core consider it reasonable to add yet another sentence to the
> > anova.glm() documentation, e.g. after the "... F test is most appropriate"
> > sentence above, adding: "(Note: unlike R, S-PLUS automatically uses the
> > moment-estimated dispersion for F-tests even for the binomial and Poisson
> > families: see ?quasibinomial.)" ?
> > Ben Bolker
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