The complementary exponential power lifetime model

In this paper we propose a new lifetime distribution which can handle bathtub-shaped, unimodal, increasing and decreasing hazard rate functions. The model has three parameters and generalizes the exponential power distribution proposed by Smith & Bain (1975) by inclusion of an additional shape parameter. Maximum likelihood estimation procedure is discussed. A small-scale simulation study examine the performance of the likelihood ratio statistics under small and moderate sized samples. Three real data sets illustrate the methodology.