Testing Whether New is Better than Used of a Specified Age

摘要

The authors introduce a new better than used at t sub o class of life distributions, where the survival probability at age 0 is greater than or equal to the conditional survival probability at specified age t sub o greater than 0. The dual class of new worse than used at t sub o life distributions is defined by reversing the direction of inequality. The authors preservation and nonpreservation properties of the two classes under various reliability operations. They then develop a test of the null hypothesis that a new item has stochastically the same residual lifelength as does a used item of age t sub o versus the alternative hypothesis that a new item has stochastically greater residual lifelength than does a used item of age t sub o.