I just wanted to check how good my Beta reg model was at recovering true values of the parameters, and I found surprisingly large differences. Same results when using the "betareg" package.
Here is an R code to simulate a Beta variable and to estimate a simple ("empty") Beta model.
Perhaps I have missed something obvious ... Any ideas?
Y = rbeta(n=1000, shape1=2, shape2=1.5) hist(Y, freq=F, xlab='', ylab='', main='') lines(density(Y, from=0, to=1), col='red') fit = betareg(Y ~ 1) mu = 1 / (1 + exp(-as.numeric(fit$coeff))) pr = as.numeric(fit$coeff) k = data.frame(true=c(2,1.5),mle=c(mu,pr)) rownames(k) = c('mean','precision') k