loglogistic survreg
On Tue, Sep 18, 2012 at 7:06 AM, Jeremy Brown <jebrown_141 at 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