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n u VeOetation Measurements /ar Bond Release: New Horizon Mine NH1 f 0 Acre Site and Reverence Area exceed 70 samples; because it appeared that mean produdion at NH1 would exceed the reference area standard, we dipped 30 plots, the minimum required for the "reverse" null hypothesis test (see following sedion). Statistical Comparisons The reference area "standard' for live perennial cover and herbaceous produdion was established as 90°k of the mean values measured for the reference area. The mean value for live perennial cover at the NH1 '10-acre site was greater than the standard, so no statistical comparison was necessary. The mean value for herbaceous produdion at the NH1 10.acre site was compared to fhe standard using the'reverse° null hypothesis test. Under the reverse null approach, aone-sided t-test with alpha enor probability of 0.20 is used to test the null hypothesis that the redaimed area sample mean is less than or equal to the reference standard (90% of the reference area sample mean). A t-statistic is calculated as where x =Reclaimed area sample mean Q =Reference standard (90% of reference area sample mean) S, =Standard error of reclaimed area sample mean (s / Jn) s =Sample standard deviation n =Sample size t° = Calculated t value t<= Table t value (one-tailed, alpha=0.20, n-1 degrees of freedom) If>c is greater than ythen the null hypothesis is rejeded, and rovegetation is deemed successful far the parameter being tested. 4.0 RESULTS. A list of common and sdentific names of plant spades appears in Appendix A Vegetation Cover Table 1 shows vegetation cover measured at 14 t4 transeds at the reference area. Table 2 shows vegetation cover measured at 25 transacts at the NH1 10-atxe site. Sample adequacy values are also shown at the bottom of each table. Mean cover at the reference area was 23.1 %; the reclamation standard is equal l0 90% of the mean, or 20.0°h. Mean cover at the NH1 10.acre site was 39.7%, which exceeds the reclamation standard and so revegelalion for cover is deemed complete. Vegetation Production Table 3 shows herbaceous produdion measured at 26 plots in the reference area. Table 4 shows herbaceous produdion measured at 30 plots in the NHt 10-acre site. Sample adequacy values are shown at the bottom of each table. Mean production at the reference area was Bf0-Logic Envlronmsnhl September 2005 • 13