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null" approach using a parametric test of the "reverse null" hypothesis. This would be conducted using the following expression (CDMG 2003 proposed rules revisions, 4.15.11 (2)(c)): _x-Q t~ S- x Where: z =Bond Release Block Sample Mean Q = 90% of Standard S_ =Standard error of mean [s/~] x S =Sample standard deviation n =Sample size k = Calculated t value t, = Table t value The null hypothesis being tested was that the bond release block mean (µ) was less than or equal to 90% of the standard, stated as H°: µ < O. If k was greater than the 1-tailed t table value • for alpha error probability of .20, with (n-1) degrees of freedom (infinite degrees of freedom may be used if n>30), then Ho was rejected, and revegetation is deemed successful. For the above (one-sample) t-test, it is necessary to have achieved sample adequacy in the reference area sampling. Were adequacy NOT to have been achieved in the reference areas, then the more complex calculations associated with atwo-sample t-test (CDMG 2003 proposed rules revisions) are undertaken. Cover was addressed in hypothesis testing as percent absolute first hit herbaceous vegetation cover as adjusted for excessive contribution by annual 1 biennial species (CDMG 1995, Guidelines Regarding Selected Coal Mine Bond Release Issues, 1 (IV)A(4)). Cover from reclaimed area samples was addressed as total percent first hit herbaceous cover. Cover from reference area sampling was first hit herbaceous cover DOUBLED (see explanation of cover performance standard as per permit, above). Hypothesis testing for production was based on total annual herbaceous production also adjusted for excessive contribution of annual /biennial species. Herbaceous cover or production values used in hypothesis testing excluded values for species present on the Routt County Prohibited or Restricted Noxious list or that were listed as noxious by the State of Colorado (Colorado Dept. of 8