1. Department of Mathematics, City University of Science and Information Technology Peshawar, Peshawar 25000, Pakistan
2. Department of Statistics, Quaid-i-Azam University, Islamabad 44000, Pakistan
3. Department of Statistics, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan
4. Pakistan Institute of Development Economics, Islamabad 44000, Pakistan
5. Department of Mathematical Sciences, College of Science, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia