Statistical Trend Analysis of Residential Water Demand in Kisumu City, Kenya
American Journal of Theoretical and Applied Statistics
Volume 4, Issue 3, May 2015, Pages: 112-117
Received: Mar. 30, 2015; Accepted: Apr. 9, 2015; Published: Apr. 18, 2015
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Robert Nyamao Nyabwanga, Department of Mathematics, Kisii University, Kisii, Kenya
Edgar Ouko Otumba, Department of Statistics and Actuarial Science, Maseno University, Maseno, Kenya
Fredrick Onyango, Department of Statistics and Actuarial Science, Maseno University, Maseno, Kenya
Simeyo Otieno, School of Business and Economics, Jaramogi Oginga Odinga University, Bondo, Kenya
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This study sought to analyse trend in the monthly water demand data series in Kisumu city at both seasonal and non-seasonal levels using the parametric method of Ordinary Least Squares (OLS) and non-parametric methods of Mann-Kendall tau and Sen's T test. Sen’s test was applied to validate the Mann Kendall trend test and to estimate the magnitude of the trend and its direction. The significance of the slope of the OLS equation was tested using the F-Test based on the Analysis of Variance (ANOVA). Secondary monthly water consumption data obtained from KIWASCO for the period January 2004 to December 2013 were used. Using logarithmically transformed data, the study established by OLS that residential water demand in Kisumu City had a significant increasing trend (FCalc=(105.13) > F(1;119)(α=0:05)=(5.15)). Kendall's tau test corroborated the OLS results of a significant increasing trend. The Sens T test indicated that most of the months registered significant upward trend with Sen’s slope estimates showing positive rates of change in residential water demand for these months.
Trend, Kendall’s Tau, OLS, Sen’s T, Residential Water Demand
To cite this article
Robert Nyamao Nyabwanga, Edgar Ouko Otumba, Fredrick Onyango, Simeyo Otieno, Statistical Trend Analysis of Residential Water Demand in Kisumu City, Kenya, American Journal of Theoretical and Applied Statistics. Vol. 4, No. 3, 2015, pp. 112-117. doi: 10.11648/j.ajtas.20150403.16
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