Laserfiche WebLink
2 2 <br />Nmin= t S <br />(d Xbar)Z <br />Where: <br />Nm;°= minimum sample size <br />t= the "T" distribution value at the 90% confidence level <br />s= sample standard deviation <br />sz= sample variance <br />d= percent acceptable deviation from the mean (10%) <br />Xba~= sample mean <br />Sample adequacy was achieved for vegetation cover and productivity. Minimum sample size <br />(Nm;n) is reported on Tables 2 and 3. <br />Statistical Analysis <br />Evaluation of revegetation establishment and success was accomplished through a <br />comparison of the reclaimed area mean and the approved permit revegetation success <br />standards, permit page 2.05.4(2)(e)-4. A "student's t-test" was used for the statistical <br />comparison. This analysis is consistent with the recommendations of the Colorado Division of <br />Minerals and Geology in the April 18, 1995 Guideline regarding selected Coal Mine Bond <br />Release Issues. Plant species relative cover derived from quantitative total cover information <br />provided the basis for assessment of species composition. <br />III. Results <br />Revegetation Success Standards <br />Cover: 41 <br />Production: 514 Ibs/acre (air dry weight) <br />Shrub Density: No shrub density requirement <br />Species Diversity: At least three perennial grass species, each contributing at least 3%, but <br />not greater than 60% relative cover. At least one of these species will be a warm season <br />grass and at least one shall be a cool season grass. <br />Cover <br />Twenty-three plant species were encountered during the cover sampling. Mean live vegetative <br />cover calculated from the data collected is 43.2% (Table 2). This value is greater than the <br />revegetation standard of 41%. The revegetation on the reclaimed area achieved the <br />vegetation cover success standard for 2003. Vegetative cover data also achieved sample <br />adequacy. <br />