The xgamma Distribution: Statistical Properties and Application

Abstract

A new probability distribution, the xgamma distribution, is proposed and studied. The distribution is generated as a special finite mixture of exponential and gamma distributions and hence the name proposed. Various mathematical, structural, and survival properties of the xgamma distribution are derived, and it is found that in many cases the xgamma has more flexibility than the exponential distribution. To evaluate the comparative behavior, stochastic ordering of the distribution is studied. To estimate the model parameter, the method of moment and the method of maximum likelihood estimation are proposed. A simulation algorithm to generate random samples from the xgamma distribution is indicated along with a simulation study. A real life dataset on the remission times of patients receiving an analgesic is analyzed, and it is found that the xgamma model provides better fit to the data as compared to the exponential model.