Analysis and Optimum Plan for 3-Step Step-Stress Accelerated Life Tests with Lomax Model Under Progressive Type-I Censoring

In this paper, the optimum test plan and parameter estimation for 3-step step-stress accelerated life tests in the presence of modified progressive Type-I censoring are discussed. It is assumed that the lifetime of test units follows a Lomax distribution with log of characteristic life being quadratic function of stress level. The maximum likelihood and Bayesian method are used to obtain the point and interval estimators of the model parameters. The Bayes estimates are obtained using Markov chain Monte Carlo simulation based on Gibbs sampling. The optimum plan for 3-step step-stress test under modified progressive Type-I censoring is developed which minimizes the asymptotic variance of the maximum likelihood estimators of log of scale parameter at design stress. Finally, the numerical study with sensitivity analysis is presented to illustrate the proposed study.