New classes of life distributions called new better (worse) than used at age t0 in Laplacetransform order, NBUL - t0(NWUL - t0) are introduced. For the classes NBUL - t0( NWUL- t0), preservation under convolution, mixture, mixing and the homogeneous P...
New classes of life distributions called new better (worse) than used at age t0 in Laplacetransform order, NBUL - t0(NWUL - t0) are introduced. For the classes NBUL - t0( NWUL- t0), preservation under convolution, mixture, mixing and the homogeneous Poissonshock model are studied. In the sequel, we obtain a test for H0 : F is exponential versus H t1 : F is NBUL- t0 and not exponential. The critical values and the powers of this test arecalculated to assess the performance of the test. It is shown that the proposed test has highefficiencies for some commonly used distributions in reliability. Sets of real data are used asexamples to elucidate the use of the proposed test for practical problems.