Maximam likelihood estimation with welbull models when the data are grouped

The likelihood equations are given for the Weibull distribution with qtouped data* A numerical technique is described for calculating the asymptotic variance-covatiance matrix with grouped data. Results from a Monte Carlo study are then used to show that in son© cases the measured efficiencies obtained with grouped data are substantially better than those rrteasiired Cor partially grouped (censored! dataf contradicting the asymptotic efficiency predictions.