Estimation in a Two-Stage Procedure for Failure Censored Model

Abstract

A reliability setting is considered for comparing two competing equipments based on a fixed number of observations. A two stage failure censored design is proposed in which a preassigned number of items are randomised equally at the first stage and the better items are examined exclusively at the end of the second stage. Here at each stage, we consider type II censoring (see e.g. Miller (1981)) . That is, observations are made upto a common prefixed proportion of failures at each stage. For exponential responses, the exact bias and variance of the estimated failure rate difference at the end of the trial are derived. Competitors of the proposed procedure are also suggested. Some asymptotics related to all these procedures are also obtained.