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2.3 Samole Adeauacv Determination <br /> Sampling within each unit (Reference Area or Phase II Bond Release Block) was conducted to a <br /> minimum of 15 samples. From these preliminary efforts, sample means and standard deviations for <br /> total non-overlapping vegetation ground cover were calculated. The Cochran formula (below) for <br /> determining sample adequacy was used to calculate nmin, whereby the population is estimated to <br /> within 10% of the true mean (p) with 90% confidence. <br /> When the inequality(nmin <_ n) is true, sampling is deemed adequate; and nmin is determined as <br /> follows: <br /> nmin = (t 2S 2) / (O.1X )2 <br /> where: n = the number of actual samples collected (initial size = 20 or 40) <br /> t = the value from the one-tailed t distribution for 90% confidence with n-1 <br /> degrees of freedom; <br /> S Z =the variance of the estimate as calculated from the initial samples; <br /> x = the mean of the estimate as calculated from the initial samples. <br /> If the initial samples do not provide a suitable estimate of the mean (i.e., the inequality is false), <br /> a reverse null success evaluation which does not require adequacy would be employed (Rule 4.15.11 <br /> (2)(c))• <br /> 2.4 Vegetation Success Evaluation <br /> Success evaluations involve a direct comparison and, where necessary, statistical testing of the <br /> ground cover parameter. In the case of ground cover, comparisons are made against reference area <br /> data of the same year. <br /> 2.5 Sedimentoloav Evaluation <br /> The purpose of the sedimentology evaluation is to demonstrate that the completed revegetation <br /> and grading in the Phase II Bond Release Block has achieved erosion control at least equal to pre- <br /> mining levels as required in Rule 4.15.1 (2) (b) and suspended solids delivered to streamflow outside <br /> the permit area will not exceed pre-mining levels as required under Rule 3.03.1 (3) (b). The <br /> methodology used is the Revised Universal Soil Loss Equation (RUSLE) using site-specific soil and <br /> 8 <br />