1. Department of Statistics, University of Peshawar, Peshawar, Khyber Pakhtunkhwa, Pakistan
2. Department of Mathematics and Statistics, University of Swat, Swat, Pakistan
3. Department of Statistics, University of Malakand, Chakdara, Khyber Pakhtunkhwa, Pakistan
4. Institute of Numerical Sciencs, Kohat University of Science and Technology, Kohat, Pakistan