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represent the allowable herbaceous cover of the Mountain Brush Area. Details of the calculation of <br />allowable herbaceous cover are provided in Tables G -1, G -2 and G -3 for each area. <br />2012 Assessment of BRB PSCM -2 for Compliance with Phase Ill Performance Standards <br />COVER <br />As described above, sample adequacy based on first -hit values was achieved for BRB PSCM -2 and the <br />Sagebrush Reference Area, but it was not for the Mountain Brush Reference Area. Thus, in consideration <br />of the lack of a sample size sufficient to detect a 10 percent reduction in the mean with 90 percent <br />confidence (i.e. sample adequacy), the upper limit of the possible values of the true mean (with a sample <br />size of 18) was determined. This can be done in either of two ways. <br />1) Confidence Intervals <br />s 4.80 <br />C.1. = — * t = *1 . 740 = 1.97 <br />18 <br />8.72 + 1.97 = 10.69 <br />2) Sample Adequacy Expression <br />s t <br />N — d2 x 2 <br />2 t 4.80 * 1.740 <br />d = — <br />x 8.72 *18 <br />= 0.2258 <br />X" + d = 8.72 + (8.72 * 0.2258) = 10.69 <br />10.69 percent allowable herbaceous cover represents the highest possible value of the true mean for the <br />Mountain Brush Reference Area. <br />[Note in the above calculations, two - tailed t values with n -1 degrees of freedom are used. We are <br />concerning ourselves with the full range of possible values for mean, thus bi- directional concerns are <br />evident. From the CDRMS point of view this pushes the limits out further and produces the highest <br />maximum value for the mean (at 90% confidence).] <br />Calculation of 90 percent of the cover performance standard appropriate for 2012 sampling using the <br />highest possible value for the Mountain Brush Reference Area component is demonstrated below. <br />15 <br />