eng Science and Education Publishing American Journal of Applied Mathematics and Statistics 2328-7292 2019-11-08 7 5 171 177 10.12691/ajams-7-5-3 AJAMS2019753 article Yasser M. Amer yasseramer4@yahoo.com 1 Rania M. Shalabi 2 Cairo Higher Institutes, Mokattam, Cairo, Egypt The Higher Institute of Managerial Science, Culture and Science City, 6th of October, Egypt Step Stress-Partially Accelerated Life Test SS-PALT under Type-II progressive censoring with Binomial or uniform removal assuming Inverse Lomax distribution has been presented. A comparison between both removals is shown. The Newton-Raphson method is applied to obtain maximum likelihood estimators MLE of the parameters and the optimal stress-change time which minimizes the generalized asymptotic variance. A simulation study is performed to illustrate the statistical properties of the parameters. http://pubs.sciepub.com/ajams/7/5/3/ajams-7-5-3.pdf Partially accelerated life test Binominal distribution uniform distribution Inverse Lomax distribution optimal design D-optimality Monte Carlo Simulation