On Tue, Sep 18, 2012 at 7:06 AM, Jeremy Brown <jebrown_...@yahoo.com> wrote: > Hi, > > I'm trying to graph the hazard function using the survreg function with the > distributional assumptions to be loglogistic. If > h(t)=[lambda*alpha*(lambda*t)^(alpha-1)]/[1+(lambda*t)^alpha], what output > from R is alpha?
survreg() fits location-scale models, so the model being fitted is that log(survival time) has a logistic distribution with location parameter given by the regression model and scale parameter estimated in each stratum. I think that means exp(fitted values) is alpha in your parametrisation. In a model with only an intercept, that would be exp(intercept). -thomas -- Thomas Lumley Professor of Biostatistics University of Auckland ______________________________________________ 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.
