The Sri Lankan Journal of Applied Statistics (SLJAS) is an open-access, international, double-blind peer-reviewed journal published by the Institute of Applied Statistics, Sri Lanka (IASSL). The main purpose of the journal is to publish the results of original work on applications of Statistics and on theoretical and methodical aspects of Statistics. The journal also welcomes critical reviews including conceptual discussions, opinions and book reviews. Applications of Statistics in the area of Agriculture & Forestry, Medical, Dental and Veterinary Sciences, Natural, Physical Sciences, Social Sciences, Economics and Actuarial Science fall within the scope of the journal. Prof. W.N. Wickramasinghe Chief Editor Sri Lankan Journal of Applied Statistics, The Institute of Applied Statistics, Sri Lanka, 2nd Floor, OPA Building, 275/75, Prof. Stanley Wijesundera Mawatha, Colombo 07, Sri Lanka.