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• ~ SAMPLE ADEQUACY EVALUATION (CONT'D) <br />Chokecherry Mine Area x s n nmin t <br />Biomass (g/m2) 75.3 23.1 15 13.3 1.26 <br />Cover (%) 66.0 6.2 4 1.3 2.13 <br />Woodv Plant Dens~ty 147.0 23.4 4 3.6 1.26 <br />(Shrubs, #/50m ) <br />Chokecherry Reference Area <br />Biomass (g/m2) 76.1 16.9 15 7.0 1.74 <br />Cover (%) 73.7 2.1 3 0.1 6.08 <br />Woody Plant Density 173.3 5.9 3 0.2 5.09 <br />(Shrubs, #/50m ) <br />One-tailed t-tests at the 95% confidence level were calculated with means for <br />each vegetation type on reference and mine areas. The null hypothesis was <br />that the parameters measured were significantly different on the mine and <br />• reference areas. If the null hypothesis was rejected, this would indicate <br />the means were not significantly different at the chosen level of testing. <br />If the measured reference area parameter was greater than that occurring on <br />the mine area, this was acceptable. Thus, the null hypothesis could be <br />accepted (means significantly different) with an acceptable result if the <br />reference area parameter was greater than the mine area parameter. <br />The following formula was used: <br />- I7t +n 2 S12+S22 <br />X1 - X2 (0. 5, nl 2- ) nl n2 where <br />X = mean values of two means being compared <br />t = the one-tai led tabular t-value at the 95% <br /> confidence level with appropriate degrees <br /> of free don (nl + n2-2) <br />S2 = the varianc e of each sample <br />n = the number of observations in each sample <br /> <br />