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. value for alpha error probability of 0.20, with (n-1) degrees of freedom (infinite degrees of <br />freedom may be used if n>30), then Ho is rejected, and revegetation is deemed successful. <br />For the above (one-sample) t-test, it will be necessary to have achieved sample adequacy in <br />the reference area sampling. If adequacy is not achieved in the reference area, then the <br />more complex calculations associated with a two-sample t-test would be undertaken. <br />Reclaimed area cover will be addressed in hypothesis testing as percent absolute all hit <br />herbaceous vegetation cover as adjusted for excessive contribution by annual / biennial <br />species (CDRMS 1995, Guidelines Regarding Selected Coal Mine Bond Release Issues, 1 <br />(IV)A(4)). Cover from reclaimed area samples will be addressed as percent absolute all hit <br />herbaceous cover. Cover from reference area sampling will be all hit herbaceous cover. <br />Hypothesis testing for production will be based on total annual herbaceous production also <br />adjusted for excessive contribution of annual / biennial species. Herbaceous cover or <br />production values used in hypothesis testing will exclude values for species present on the <br />Routt County Prohibited or Restricted Noxious list or that are listed as noxious by the State <br />of Colorado (Colorado Department. of Agriculture, Division of Plant Industry, Title 35, <br />Article 5.5, 101-119, Lists A and B of Rules as replaced 2003). <br />Species Diversity <br />Species diversity suitable to support the approved post-mining land uses of rangeland and <br />wildlife habitat will be judged using the following four (4) tests. Success would be <br />• demonstrated by passing the first (A) and at least two of the remaining three (B, C, and D). <br />Mandatory Test A: No Overwhelming Dominant - No single plant species may exceed 60 <br />percent relative cover. <br />Alternative Test B: Total Species Density Test - It is proposed that this overall <br />reclamation diversity standard be judged based on the species density values observed <br />along with cover sampling in 100 square in sample plots (see species density sampling <br />discussed above). It is further proposed that the species density numbers be subjected to <br />sample adequacy assessment in the usual manner. For purpose of establishing the range of <br />species density within the reference areas, the 75 percent range of variation would be <br />established as: <br />(z) * (s) <br />Where: <br />z = the number of standard deviations (both ways from the mean) encompassing 75 percent <br />of the normal distribution (= 1.15; see Rohlf and Sokal 1969, Table P) <br />s = standard deviation (n-1) <br />* means multiply <br />The standard would be the point at which the central 75 percent of the distribution of <br />• overall species density in the reference areas begins. Mathematically this would be: <br />PR-02 2.05.4-6 10/10