1. Department of Statistics, Federal University of Technology Akure, Akure, Nigeria
2. Department of Statistics, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa
3. Department of Mathematical Statistics and Actuarial Sciences, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein, South Africa
4. Department of Statistics, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia