Hi, I am trying to run a generalized linear regression using a negative binomial error distribution. However, I want to use an overdispersion parameter that varies (dependent on the length of a stretch of road) so glm.nb will not do.
>From what I've read I should be able to do this using GLM by specifying my own quasi family and describing the variance function using varfun, validmu, dev.resids and initiate. However I cannot find any detailed discussion of this method. Any help would be appreciated. ps I've done this in SAS so I know it should be possible! Craig ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.