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Reference Area, the Sagebrush Reference Area and the Steep Mountain Brush Reference Area but it <br />was not for the Mountain Brush Reference Area. <br />In consideration of the lack of a sample size sufficient to detect a 10 percent reduction in the mean with <br />90 percent confidence (i.e. sample adequacy), the upper limit of the possible values of the true mean <br />(with a sample size of 18) was determined for the Mountain Brush Reference Area. This can be done <br />either by calculating the confidence interval for 90% confidence and adding it to the mean or by way of <br />rearranging the sample adequacy formula and solving for the detectable percent reduction then adding <br />that to 100% and multiplying by the mean. This is demonstrated in the Discussion section below. <br />It is also to be noted that the data from the four Yoast Mine reference areas is weighted in accordance <br />with the original relative abundance of the types in the pre- mining landscape (24.4% Aspen, 48.9% <br />Mountain Brush, 24% Sagebrush /Snowberry and 2.7% Steep Mountain Brush). In the process of <br />weighting, a reliable estimate of variance is lost. Thus the reference area standard thereafter in the <br />process is treated as a technical standard (i.e. without confidence limits) and one - sample t- testing is <br />used. <br />HYPOTHESIS TESTING APPROACHES <br />For formal hypothesis testing relative to Phase III Bond Release the following procedures were followed: <br />Cover and Production <br />Phase III Revegetation success for cover and production will be demonstrated by one of following <br />statistical approaches. <br />If sample adequacy has been achieved (minimum of 15 samples) in BRB -1 and the reference areas, and <br />the reclaimed area mean total allowable herbaceous cover and mean allowable herbaceous production <br />are above 90% of the reference area - derived standard, all criteria are met for a direct comparison and <br />revegetation would be deemed successful (CDMG 2005 revised rule, 4.15.11 (2)(a)). <br />Were the mean allowable herbaceous cover and /or production of the reclaimed area above 90% of the <br />reference area - derived standard, and sample adequacy was not met for the reference areas and /or BRB- <br />1 (minimum of 30 samples, technical standards not subject to sample adequacy), then the hypothesis of <br />reclamation success would be tested using a parametric test of the "reverse null" hypothesis. This would <br />be conducted using the following expression (CDMG 2005 revised rule, 4.15.11 (2)(c)). <br />6 <br />