On Hybrid Censored Weibull Distribution Debasis Kundu Abstract A hybrid censoring is a mixture of Type-I and Type-II censoring schemes. This arti- cle presents the statistical inferences on Weibull parameters when the data are hybrid censored. The maximum likelihood estimators and the approximate maximum likeli- hood estimators are developed for estimating the unknown parameters. Asymptotic distributions of the maximum likelihood estimators are used to construct approximate confidence intervals. Bayes estimates and the corresponding highest posterior density credible intervals of the unknown parameters are obtained under suitable priors on the unknown parameters and using the Gibbs sampling procedure. The method of obtain- ing the optimum censoring scheme based on the maximum information measure is also developed. Monte Carlo simulations are performed to compare the performances of the different methods and one data set is analyzed for illustrative purposes. Keywords: Maximum likelihood estimators; approximate maximum likelihood estimators; asymptotic distribution; Type-I censoring; Type-II censoring; Gibbs sampling, Optimum censoring scheme. Corresponding Address: Department of Mathematics and Statistics, Indian Institute of Technology Kanpur, Pin 208016, INDIA. Phone: 91-512-2597141; Fax: 91-512-2597500; e-mail: kundu@iitk.ac.in 1