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• When the inequality (n,n;n <_ n) is true, sampling is deemed adequate; and nrn;n is determined as <br />follows: <br /> <br />where: n =the number of actual samples collected (initial size = 15 or 20) <br />t =the value from the two-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 plculated 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 />additional samples would be collected until the inequality (nmin <_ n) becomes true. However, because <br />sampling is for managerial (monitoring) information, adequacy is not necessary and is calculated for <br />informational purposes only. <br />J <br />7.0 Success Evaluation <br />7.1 Ground Cover and Production <br />Success evaluations involve a direct (and perhaps statistical test) comparison of appropriate <br />parameters for each variable of interest. During monitoring efforts, comparisons are made directly with <br />either the reference area parameters or the permitted standards. In the case of ground rnver and <br />production, comparisons are made against reference area data of the same year. <br />In 2004, Cedar Creek was able to make direct comparisons between revegetated units and <br />reference areas with regard to the variable of ground cover for all units 2 years of age or older, and for <br />production for all units 7 years of age. Charts 3, 4, and 5 were developed to provide a quick overview of <br />the success of these revegetated efforts in comparison to reference areas. Once sufficient reference area <br />data are available (from several years of collection), a regression may be developed between <br />precipitation and ground cover (and production) to develop a "guideline" for such wmparisons that would <br />• fadlitate managerial decision-making on the part of Cobwyo reclamation staff. frolkwving development of <br />such a regression, reference area sampling could cease unless bond release testing is scheduled. <br />KenneCOn Energy / Cobwyo Coal Company AA -7 Revegetallon Monitoring -2004 <br />