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APPENDIX D <br /> STATISTICAL EVALUATION OF CONCENTRATION TRENDS <br /> The Kendall Rank Correlation test for trend, also called the Mann-Kendall test, is a <br /> nonparametric, rank correlation method that can be used for evaluating correlations <br /> between time and constituent concentrations The test is described in "Statistical Methods <br /> for Environmental Pollution Monitoring" (Richard O Gilbert, Van Nostrand Company, <br /> New York, 1987) and in "Nonparametric Statistical Methods" (Myles Hollander and <br /> Douglas A Wolfe, John Wiley and Sons, New York, 1973) Its use is recommended in <br /> "An Evaluation of Trend Detection Techniques for Use in Water Quality Monitoring <br /> Programs" (J C Loftis et al , Environmental Protection Agency, 1989) <br /> The Kendall Rank Correlation test is nonparametric, meaning that it does not depend on <br /> an assumption of a particular underlying distribution. The test uses only the relative <br /> . magnitudes of the data rather than their actual values, therefore, missing values are <br /> allowed, and constituents which are not detected can still be used in the statistical analysis <br /> by assigning values equal to half their detection limits <br /> To determine if constituents exhibit statistically significant trends, the Kendall Rank <br /> Correlation Test for trend was applied using the StatView computer program (Abacus <br /> Concepts, 1992) For the Safeway monitoring program, the null hypothesis, Ha, is that no <br /> trend of constituent concentrations exists over time. The alternative hypothesis, H., is that <br /> either an upward or downward trend of constituent concentrations exists The results for <br /> the trend analyses are contained in this appendix <br /> SAC\N\PJ2\2794\2794 1000 ICS-99V=ner 6 Emcon <br /> D-1 Iter+ 0,722/98 <br />