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ERO Resources <br />• <br />121 S~,mle A .a y Testing: <br />Sampling adequacy was tested using cover values, shrub and tree density <br />and primary productivity. The formula applied to sampling adequacy <br />testing as follows: <br />2 <br />txSD <br />Minimum Sample Number = <br />d x X <br />where t = the t statistic at the lOX or 20X confidence <br />interval t 0.10 [21= 1.64, t 0.10 [21= 1.28 <br />50 = the standard deviation of the sample <br />d the x error desired in the sample I10X in these <br />calculations) <br />X = the sample mean <br />f3) Student t-Test: <br />• A Student t-test was employed to test potential differences between <br />affected vegetation types and their corresponding reference areas. Cover <br />values in all categories li.e., ground cover, herb cover, shrub cover and <br />primary productivity) as well as shrub density were used in this <br />analysis. The null hypothesis -- Ho: affected = reference )the two <br />stands tested are equal in cover, density or productivity) was accepted if <br />the calculated t-value was less than the critical t-value at the 0.05 <br /> <br />level with the appropriate degrees of freedom. The actual equation for <br />calculating the t-value was taken from Sokol and Rohlf 119691. <br />II.F- 9 <br />