PRESERVATION OF SOME NEW PARTIAL ORDERINGS UNDER POISSON AND CUMULATIVE DAMAGE SHOCK MODELS

Abstract

G(t)denote the survival functions of the first and second device respectively. In this paper we show that some new partial ordering, namely dual (D), dual stochastic (DST), dual weak likelihood ratio (DW LR), increasing failure rate (IFR ), dual mean residual lives (DM RL)and dual convex ( DCX)orderings between the shock survival probabilities ¯ Pk and ¯ Qk are preserved by the corresponding survival function ¯ F (t)and ¯ G(t). We also obtain sufficient condition under which the above mentioned relations between the discrete distributions are verified in some cumulative damage shock models.