THE NEW BETTER THAN USED IN THE EXCESS WEALTH ORDER CLASS OF LIFE DISTRIBUTIONS

Document Type : Research and Reference

Authors

1 Taibah University, Madina Munawara, Saudi Arabia

2 Sadat Academy for Management Science, Egypt

Abstract

Comparisons between the life distribution of a new unit with that of the long term remaining life or a used unit in excess wealth order, have led us to introduce a new class of life distributions. This is the new better than used in excess weather (NBUW). The relation of this class to other classes of life distributions, closure properties under three reliability operations are discussed. Stochastic comparisons of the excess life time at different times of a renewal process when the inter-arrival times belong to the NBUW class are established. We also provide a simple argument based on stochastic order that the family of the NBUW distributions is closed under the formation of parallel systems in case of independent but not identically distributed components. We add a new result when the stochastic comparisons are given in terms of total time on test transform ordering. Also we show that if the inter-arrival times belong to the NBUW class, then excess life time at t can be compared with the excess life time at time 0.