FITTING THE STATISTICAL DISTRIBUTION FOR DAILY RAINFALL IN IBADAN, BASED ON CHI-SQUARE AND KOLMOGOROV- SMIRNOV GOODNESS-OF-FIT TESTS.

Abstract

This paper presents several types of statistical distributions to describe rainfall distribution in Ibadan metropolis over a period of 30 years.The exponential, gamma, normal and poisson distributions are compared to identify the optimal model for daily rainfall amount based on data recorded at rain guage station at Forestry Research Institute of Nigeria, Jericho, Ibadan (FRIN). The models are evaluated based on chi- square and kolmogorov-smirnov tests. Overall, this study has shown that the exponential distribution is the best model followed by normal and poisson model that has the same estimated rainfall amount for describing the daily rainfall in Ibadan metropolis.

Keywords: scale parameter, asymptotically, exponential distribution, gamma distribution, poisson and kolmogorov-smirnov.