“…Commonly used methods are constant-stress, step-stress, and progressive-stress, see, for example, Nelson,12 AL-Hussaini and Abdel-Hamid, 13,14 and Abdel-Hamid and AL-Hussaini. 15 The stress applied to a test product increases in time during a progressive-stress ALT, see, for example, Yin and Sheng, 16 Abdel-Hamid and AL-Hussaini, 17 Abdel-Hamid and Abushal, 18 and AL-Hussaini et al 19 Censoring is very common in life tests. It may be applied when the experimenter is unable to get total information on lifetimes for each unit or to reduce the total test time and the associated cost.…”