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revisions, 4.15.11 (2)(c) and as set forth in McDonald et al. 2003). <br />The reverse null hypothesis states the mean of a given vegetation parameter in the revegetation area <br />(pbr) is equal to or less than 90% of the mean on the reference area (pref). <br />H ,u —0.9 *P < <br />Ha: Pbr — 0.9* p ref > 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 />t = <br />X — (19..lref <br />Sb + (0.9 * S. ef ) 2 <br />n br 1Z ref <br />and the degrees of freedom are: <br />4 <br />SE: <br />df sar (� (� l <br />( JE+b (0.9 * JE r1et )4 ) <br />11 — 1 n f —1 J <br />Where: x br = revegetation sample mean, <br />. ref = reference area sample mean, <br />S2br = revegetation area variance, <br />S Z ref = reference area variance, <br />SE = revegetation area standard error of the mean, <br />SEref = reference area standard error of the mean, <br />SEsat = denominator of the t- statistic, <br />nbr = revegetation area sample size, and <br />n fef = reference area sample size. <br />Revegetation is successful when the one -sided null hypothesis is rejected: the test statistic is greater than <br />t 1_a,df . 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 less than <br />90% of the cover standard (see above), then a one - sample t -test would be made in the following form to <br />test the hypothesis of reclamation success for cover <br />7 <br />