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x =Sample arithmetic mean <br />t = The (a=.10) t-table value for a 1 tail t-test, n-1 degrees of <br />freedom (infinite degrees of freedom may be used if <br />n>30) see Rohlf and Sokal (1969) <br />n = Sample size <br />NOTES ON THE COMPARISON OF DATA TO APPLICABLE REFERENCE AREA STANDARDS <br />Upon the formal comparison of cover data from reclaimed areas to applicable performance <br />standards, observed total first-hit herbaceous cover percentage must be adjusted for excessive <br />contribution by annual / biennial species (CDMG 1995, Guidelines Regarding Selected Coal Mine <br />Bond Release Issues, 1 (IV)A(4)). Herbaceous cover values used in such comparisons also must <br />exclude values for species present on the Routt County Prohibited or Restricted Noxious list or <br />that are listed as noxious by the State of Colorado (Colorado Dept. of Agriculture, Division of <br />Plant Industry, Title 35, Article 5.5, 101-119, Lists A and B of Rules as replaced 2003). Of course <br />given the need to address herbaceous cover, values attributable to woody species are also <br />subtracted. <br />For purposes of assessment of reclamation adequacy, all-hit herbaceous cover data from <br />reference area sampling is used as per Yoast Mine permit provisions. <br />It is also to be noted that the data from the four reference areas is weighted in accordance with <br />the original relative abundance of the types in the pre-mining landscape (Aspen - 24.4%, <br />Mountain Brush - 48.9%, Sagebrush/Snowberry 24.0%, and Steep Mountain Brush - 2.7%). It <br />was necessary to sample each to adequacy (see below) but in the process of weighting, a <br />reliable estimate of variance is lost. Thus the reference area standard is thereafter in the process <br />treated as a technical standard (i.e. without confidence limits) and one-sample t-testing is used. <br />HYPOTHESIS TESTING APPROACHES <br />For formal hypothesis testing relative to Phase II Bond Release the following procedures were <br />followed: