1. Visiting Research Fellow, University of Malaya, Kuala Lumpur, Malaysia
2. Department of Mathematics, Islamic University, Kushtia, Bangladesh
3. Unit for the Enhancement of Academic Performance, University of Malaya, Kuala Lumpur, Malaysia
4. Department of Applied Statistics, Faculty of Economics and Administration, University of Malaya, Kuala Lumpur, Malaysia
5. Department of Statistics Jahangirnagar University, Dhaka, Bangladesh