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I wonder if someone has tried to implement the hierarchical generalized linear model (HGLM) approach of Lee and Nelder (JRSSB, 1996, 58: 619-56) in R. Thanks in advance. Emmanuel Paradis At 17:18 01/04/02 +0100, ripley at stats.ox.ac.uk wrote: >On Mon, 1 Apr 2002, Jason Liao wrote: > >> Happy new month, everyone! >> >> I am planning to write a NIH grant proposal to study ways to speed >> M...

Christoph Lehman had problems with seperated data in two-class logistic regression. One useful little trick is to penalize the logistic regression using a quadratic penalty on the coefficients. I am sure there are functions in the R contributed libraries to do this; otherwise it is easy to achieve via IRLS using ridge regressions. Then even though the data are separated, the penalized

The compositional data xi=(x_i1,x_i2,...,x_in), for each fixed i , xij>0, and sum(xij)=1; I want to compare the mean( u_i) of several groups i.e. H0: u_1=u_2=...=u_N or H0: u_11=u_21=...=u_N1 Are there any ANOVA tpye tools to do this work in R? Thanks, WEN S Q [[alternative HTML version deleted]]

I would like to fit a logistic regression using a smothing spline, where the spline is a piecewise cubic polynomial. Is the knots option used to define the subintervals for each piece of the cubic spline? If yes and there are k knots, then why does the coefficients field in the returned object from gam only list k coefficients? Shouldn't there be 4k -4 coefficients? Sincerely, Bill

...Although they are most often used for continuous response variables they work perfectly well for counts. Stata 7.0 does the Newey-West estimator for generalised linear models, which may be what you had heard about. These and related sandwich-type estimators are reviewed by Lumley & Heagerty (JRSSB 1999,pp459-477). I have R code, but again only for generalised linear models, not for zero-inflation models." Thomas added: - The Poisson-Normal model leads to a loglinear marginal model that can be fitted by glm(), and I would expect something similar to be true of the zero-inflation model...

Hi, Is it possible to compare two GAM objects created with the gam() function from the mgcv package. I use a slightly modified version of anova.glm() named anova.gam(), modified from John Fox (2002). It often gives me some aberant responses, especially with "F" test. I use a quasibinomial model and scale (dispersion) is calculated and used in the calculation of the F value. Does someone

Hello. Douglas Bates has explained in a previous posting to R why he does not output residual degrees of freedom, F values and probabilities in the mixed model (lmer) function: because the usual degrees of freedom (obs - fixed df -1) are not exact and are really only upper bounds. I am interpreting what he said but I am not a professional statistician, so I might be getting this wrong... Does