Laserfiche WebLink
Q = 90% of Standard <br />. S_ = Standard error of mean [ s / F ] <br />X <br />S = Sample standard deviation <br />n = Sample size <br />tc = Calculated t value <br />tt = Table t value <br />The null hypothesis being tested would be that the bond release block mean (µ) was less than or <br />equal to 90% of the standard, stated as Ho: µ <_ Q. If tc was greater than the 1-tailed t table value <br />for alpha error probability of .20, with (n-1) degrees of freedom (infinite degrees of freedom may <br />be used if n>30), then Ho was rejected, and revegetation would be deemed successful. <br />For the above (one-sample) Mest, it is necessary to have achieved sample adequacy in the <br />reference area sampling. Were adequacy NOT to have been achieved in the reference areas, <br />then the more complex calculations associated with a two-sample t-test (CDMG rules) are <br />undertaken. <br />Cover was addressed in hypothesis testing as percent absolute all-hit herbaceous vegetation <br />• cover as adjusted for any contribution of noxious weeds, and excessive contribution by annual / <br />biennial species (CDMG 1995, Guidelines Regarding Selected Coal Mine Bond Release Issues, <br />1 (IV)A(4)). <br />Performance Standards for Use in Interim Monitoring Assessment <br />COVER and HERBACEOUS PRODUCTION: For purposes of comparison only, cover and <br />herbaceous production performance standards were calculated in accordance with procedures <br />contained in the Yoast permit. A line that indicates 90 percent of this standard has been placed <br />on Figures 1 a and 2 for informational purposes. At such time as bond release is formally sought, <br />revegetation will be considered successful for cover when mean cover for a bond release block is <br />at least 90% of the calculated success standard or approved technical standard. <br />WOODY PLANT DENSITY: For purposes of comparisons in this document, general (background) <br />woody plant density at the Yoast Mine is evaluated using a technical standard of 200 shrubs per <br />acre. Shrub concentration areas such as may be included in eventual bond release blocks are <br />judged by a standard of 2000 stems per acre. <br />• <br />7