年龄点t0之后的NBU性的非参数检验方法

NBU＊t0寿命分布中新元件的寿命随机地大于旧的年龄不小于t0的元件的剩余寿命，这为更广泛地模拟元件的老化和劣化现象提供了丰富的内容。本文首先对那些t0年龄点之后剩余寿命随机等于新元件寿命的元件的结构加以刻画，然后建立了一个非参数检验方法以区分这种随机等价性和t0年龄点后的严格的NBU性，并给出了针对一个NBU＊t0但非NBU的寿命分布的例子的数值模拟结果。

Nonparametric Test for Whether New is Strictly Better than Used since Age to

NBU*to class of life distributions, characterized by the fact that a new item has a stochastically larger life length than the residual life length after a certain age to＞0, is studied in thispaper, we first provide a characterization for those the residual life of a used one with age not less than t0＞0 is stochastically equivalent to that of a new one. Furthermore, a nonparametric test is designed so as to test the stochastic equivalence between the life length of a new item and that of a used one with an age greater than to, against the alternative, that there is a great tendency for a new item to have a strictly longer life length than does a used one with age not smaller than to. Since computer-intensive method is avoided, it is simpler and more convenient than that in Zehui, Li and Xiaohu, Li. Finally, some numerical simulations are presented.