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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 />Ho Pb, — 0.9 * µrer < 0 <br />Ha µbr — 0.9 * µref > 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 xbr __ 0.9.xre f <br />= <br />r 0.9 *Sref)2 + nref <br />and the degrees of freedom are: <br />d SE4 <br />s.I <br />fsor = (SE4 +(0.9 *SE7 4 <br />ef)) <br />nbr —1 nref —1 <br />Where: xbr= revegetation sample mean, <br />x1ef = reference area sample mean, <br />s2b, = revegetation area variance, <br />s2,f = reference area variance, <br />SE& = revegetation area standard error of the mean, <br />SE,,f = reference area standard error of the mean, <br />SEsaf = denominator of the t -statistic, <br />nbr = revegetation area sample size, and <br />n,f = reference area sample size. <br />Revegetation is successful when the one -sided null hypothesis is rejected: the test statistic is greater than <br />t,_. d& . 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 />