Dear R users, I'd like to fit different longevities for males and females (µm vs µf below) with a Weibull interval-censored survival model. Unfortunately more than 50% of the individuals in the experiment died before their sex could be assigned. Hence I was wondering about fitting the proportion of females in the model ( "prop" below) with a likelihood function such as: L(prop, µf, µm, shape)=prop*L(µf, shape)*(1-prop)L(µm, shape). I tried to follow the Cauchy example, but I realized that I don't have a proper density function to be passed on to the survreg.fit function. Does anyone has an advice on how to implement that in R? Thank you very much! Best regards, N. Rode CEFE (Centre d'Ecologie Fonctionnelle et Evolutive) UMR 5175 CNRS, 1919 route de Mende 34293 Montpellier, France [[alternative HTML version deleted]]