Testing the stochastic order and the IFR,DFR, NBU,NWU ageing classes

This paper develops new tests of exponentiality against IFR (DFR) and NBU (NWU) ageing classes. The test for the stochastic order is considered first, and the measure of deviation for the stochastic order forms the basis of tests for the ageing classes. For these tests, the authors obtain the exact distribution and asymptotic properties. Their tests are compared with other tests for ageing classes.