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where: <br />7 Xbar= sample mean <br />J S =sample standard deviation <br />n =number of samples <br />SZP = (v2tS2t+v22S2~/ v2t+v22 pooled variance <br />Sx~_~= sgrt[SZP(nt+n2~ntn2)] standard error of the difference between the <br />means <br />The values are: <br />Area 2 Reference Area <br />Xbar 21.88 22.67 ° <br />S 4.81 4.21 <br />0 16 12 <br />v 15 11 <br />Sep = vztS2~+v22S22/ vet+v22 =[(15)2(4.81)2+(11)2(4.21)2]!(15)2+(11)2 <br />SZP =21.24 <br />Sxt-zz= sgrt[SZP(nt+n2~n~n~l = sgrt[21.24[16+12/(16)(12)]] = sgrt[3.1O] <br />Sxl-x2= 1.76 <br />The t test equation with the sample cover data becomes: <br />t = [21.88-(0.9)x(22.67)]/1.76 <br />0 <br />t = 0.84 ° <br />The critical value of the t statistic for 90% confidence, one-tailed test, with 26 degrees <br />of freedom is 1.315. Since the calculated t value is less than the critical value, the <br />original hypothesis (I-Io : µ„~„ 2 > O.9µ,~f~~e ~ is not rejected. The statistical <br />conclusion is that the Area 2 revegetated areas meet the revegetation success criterion <br />for cover at this time. These areas have live aerial vegetation cover equal to or greater <br />than 9030 of the 22,67% Upland Sagebrush Reference Area aerial vegetation cover <br />with 90% statistical confidence, These areas qualify at this time for Phase II Bond <br />Release based on the vegetation cover criterion. <br />IS <br />