Vithanawasam, K.; Lakshani, M.P.; Dharmarathna, R.G.R.T.; Weerakkody, W.C.L.; Herath, H.M.D.I.
(5th National Conference on Applied Social Statistics (NRCASS) - 2019, Department of Social Statistics, Faculty of Social Sciences, University of Kelaniya, Sri Lanka, 2019)