Table of Contents
Advances in Statistics
Volume 2015, Article ID 319051, 13 pages
Research Article

Estimation in Step-Stress Accelerated Life Tests for Power Generalized Weibull Distribution with Progressive Censoring

1Department of Mathematics, Faculty of Science, Al-Azhar University, Cairo, Egypt
2Department of Mathematics, Faculty of Education, Ain Shams University, Cairo, Egypt

Received 22 October 2014; Accepted 20 January 2015

Academic Editor: Shuo-Jye Wu

Copyright © 2015 M. M. Mohie EL-Din et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Based on progressive censoring, step-stress partially accelerated life tests are considered when the lifetime of a product follows power generalized Weibull distribution. The maximum likelihood estimates (MLEs) and Bayes estimates (BEs) are obtained for the distribution parameters and the acceleration factor. In addition, the approximate and bootstrap confidence intervals (CIs) of the estimators are presented. Furthermore, the optimal stress change time for the step-stress partially accelerated life test is determined by minimizing the asymptotic variance of MLEs of the model parameters and the acceleration factor. Simulation results are carried out to study the precision of the MLEs and BEs for the parameters involved.