1. Introduction
Any statistical analysis depends greatly on the statistical model used to represent the phenomena under study. Hence,
the larger the class of statistical models available to the statistician the easier it is to choose a model. A quick survey of
the models in common use reveals the abundance of statistical models in the literature. However, data of many important
and practical problems do not follow any of the probability models available. In such cases a non-parametric model may
be recommended. Although a two parameter distribution may provide reasonably precision in fitting data, it may be still
desirable to extend the flexibility of any distribution to allow for better description of data without having to resort to nonparametric
models. Since there is a clear need for extended forms of these distributions, a significant progress has been made
toward the generalization of some well-known distributions and their successful applications to problems in areas such as
engineering, finance, economics and biomedical sciences, among others. An interesting idea of generalizing a distribution,
known in the literature as Marshall and Olkin (M–O) extended distribution. In [1], a new method of adding a parameter
into a family of distributions was introduced and studied. The resulting distribution, known as M–O extended distribution,
includes the baseline distribution as a special case and gives more flexibility to model various types of data. According to [1],
if F (x) denotes the survival function (sf) of a continuous random variable X, then the timely honored device of adding a new
parameter results in another sf G(x) defined by