Inference under progressively type ii right-censored sampling for certain lifetime distributions

In this paper, estimation of the parameters of a certain family of two-parameter life-time distributions based on progressively Type II right censored samples (including ordinary Type II right censoring) is studied. This family, of reverse hazard distribu-tions, includes the Weibull, Gompertz and Lomax distributions. A new type of param-eter estimation, named inverse estimation, is introduced for both parameters. Exact confidence intervals for one of the parameters and generalized confidence intervals for the other are explored; inference for the first parameter can be accomplished by our methodology independently of the unknown value of the other parameter in this family of distributions. Derivation of the estimation method uses properties of order statis-tics. A simulation study in the particular context of the Weibull distribution illustrates the accuracy of these confidence intervals and compares inverse estimators favorably with maximum likelihood estimators. A numerical example is used to illustrate the proposed procedures. Key words: confidence interval, inverse estimator, order statistics, proportional re-verse hazard distribution. 1