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H : —0.9 * /ref < 0 <br />H : ,ubr — 0.9 * ,urer > 0 <br />Evidence in support of revegetation success is obtained when the null hypothesis is rejected. <br />Assumptions for this test include approximate normality and independence of observations between the <br />two groups. <br />The test statistic is: <br />and the degrees of freedom are: <br />t = <br />x — 0.9X <br />S b r (0 *S 7ef ) 2 <br />n br n ref <br />8 <br />SE a , <br />( SE + (0.9* SE re1 )4 <br />) <br />n br — 1 n ref — 1 <br />Where: x br is the revegetation sample mean, <br />x 7 ef = the reference area sample mean, <br />S = the revegetation area variance, <br />S 2 ref = the reference area variance, <br />SE the revegetation area standard error of the mean, <br />SE = the reference area standard error of the mean, <br />SEset = the denominator of the t- statistic, <br />nb the revegetation area sample size, and <br />nref = the reference area sample size. <br />Revegetation is successful when the one -sided null hypothesis is rejected: the test statistic is greater than <br />. The conclusion is that the revegetation mean is greater than 90% of the reference mean. <br />Were the mean allowable herbaceous cover or production of an adequate sample from the BRB Tess than <br />90% of the cover standard (see above), then a one - sample t -test would be made in the following form to test <br />the hypothesis of reclamation success for cover (CDMG 2010 proposed rules revisions, 4.15.11 (2)(b)): <br />