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• <br />ERO Resources <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 10% or 20% confidence <br />interval t 0.10 121= 1.64, t 0.10 (21= 1.28 <br />SD = the standard deviation of the sample <br />d = the % error desired in the sample (10% in these <br />calculations) <br />X = the sample mean <br />Offlopr4r.'"7r. iT-2m <br />isA 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 />11 <br />level with the appropriate degrees of freedom. The actual equation for <br />calculating the t -value was taken from Sokal and Rohlf 41969). <br />II.F- 9 <br />