I just ran example(glm) and happened to notice that models based on the Gamma distribution gives a t test, while the Poisson models give a z test. Why?
Both are b/s.e., aren't they? I can't find documentation supporting the claim that the distribution is more like t in one case than another, except in the Gaussian case (where it really is t). Aren't all of the others approximations based on the Wald idea that bhat^2 ------------ Var(bhat) is asymptotically Chi-square? And that sqrt(Chi-square) is Normal. While I'm asking, I wonder if glm should report them at all. I've followed up on Prof Ripley's advice to read the Hauck & Donner article and the successors, and I'm persuaded that we ought to just use the likelihood ratio test to decide about individual parameters. -- Paul E. Johnson Professor, Political Science 1541 Lilac Lane, Room 504 University of Kansas ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html