Abstract: Agricultural planning, drainage pattern and designs for erosion control all depends on how best the design of water management practices are been conducted. This can be, best achieved if there is a prior knowledge of the distribution pattern of rainfall characteristics. The effect of rainfall to man is diverse ranging from designs of agricultural systems to erosion control. This study is aimed at exploring the statistical distribution namely Gamma distribution on quarterly rainfall amount in Zaria. Quarterly rainfall data were been collected for a period of 38 years (1971 – 2008) from Nigeria Meteorological Agency (NMA) quoted in central bank of Nigeria (CBN) bulletin, the Gamma distribution was used to model the distribution of the quarterly rainfall amount. Kolmogorov – Smirnov, One Sample test was used to evaluate the model fit. The Gamma distribution adequately fit the quarterly rainfall data producing a suitable model base on the Kolmogorov – Smirnov One Sample test. The result could be very useful to agricultural planning, erosion control, etc.
Keywords: Chi-square test, Gamma distribution, Likelihood ratio test, quarterly, Rainfall intensity,
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