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• Statistical tests of the apparent situation that the reclaimed area production values <br />greatly exceed those of either of the reference areas is presented as follows in the form <br />of a parametric test of the "reverse null hypothesis" as per prescribed methods <br />(Colorado Coal Regulations 4.15.11 (2)(c)). <br />Relative to Mountain Brush Reference: <br />tc = (1424.1 - 634.7) / (564.1 / sgrt 30) = 7.66 <br />Since critical t = 0.845 (one-tailed, alpha = 0.2, 29 dfJ and tc is greater than this critical <br />value, reclamation success is demonstrated. <br />Relative to Sagebrush/Snowberry Reference: <br />k = (1424.1 -1038.5) / (564.1 /sgrt 30) = 3.74 <br />Since critical t = 0.845 (one-tailed, alpha = 0.2, 29 df) and t~ is greater than this critical <br />value, reclamation success is demonstrated. <br />• Since production values from the BRB-3 reclamation samples have been shown to be <br />greater than those of both reference areas, overall reclamation success for production is <br />demonstrated. <br />WOODY PLANT DENSITY <br />Figure 3 graphically presents "background" shrub density averages for reclaimed areas <br />sampled in 2006. As can be seen, all areas exceeded the 100 stem per acre <br />background standard, Because of the presence of some shrubless samples, and even <br />with sample size of fifty, sample adequacy was not even closely approximated (Table <br />16). <br />Statistical testing of the apparent situation that the reclaimed area background woody <br />plant density values greatly exceed 90% of the standard (90 stems per acre) is <br />presented as follows in the form of a parametric test of the "reverse null hypothesis" as <br />per prescribed methods (Colorado Coal Regulations 4.15.11 (2)(c)). <br />• t~ _ (1833 - 90) / (4743 /sgrt 50) = 2.60 <br />24 <br />