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• <br />• <br />• <br />If the initial minimum number of samples in each area did not provide a suitable estimate of the mean <br />(i.e., the inequality was false), additional samples were collected until the inequality (nmin < n) became <br />true. Only two areas required additional sampling (Juniper Scrub and Bottomland Baseline Areas) where <br />39 and 17 additional production samples were collected. <br />Reference Area Comparability - When reference areas are utilized as revegetation standards of success for <br />vegetation cover and production, demonstrations are required prior to permit issuance to document that <br />the selected reference areas are statistically comparable (equal) to the vegetation types for which they <br />represent. The pre- mining demonstration of reference area comparability was made using the two- tailed <br />Students t -test as indicated below. Reference area production and cover are compared at the 95 percent <br />confidence limit (alpha at 0.05 level) with the respective baseline area production and cover. The sample <br />"t" statistic (t *) is calculated as follows: <br />The tabular "t" comparison statistic (t ) is calculated as follows: <br />Then if the inequality (t* < t ' a ) is true, the test is passed and the baseline and reference areas can be <br />considered to be from identical populations. <br />Results <br />Collom — Rule 2, Page 60 <br />t * =(x, — x +(s /n <br />where : <br />x, = mean of the baseline area <br />x 2 = mean of the reference area <br />s 2 1 = variance of the baseline area <br />s 2 2 = variance of the reference area <br />n = sample size for the baseline area <br />n sample size for the reference area <br />t; = [( /n + (s22 /n2)ta2]/(s,2 /n, + s /n <br />where : <br />O = 0.05 level <br />RULE 2 PERMITS <br />Detailed Vegetation Information <br />General - Six major vegetation community types were identified within the Vegetation Study Area: <br />Aspen, Sagebrush, Bottomland, Grassland, Juniper Scrub, and Mountain Shrub. Minor vegetation <br />communities and land use types included: Improved Pasture, Cultivated Land (Cropland), Disturbed <br />Areas, and Wetlands (acres of wetlands and waters of the U.S. are included under the Bottomland <br />vegetation community type). The acreage occupied by each type /subtype are indicated in Table 2.04.10 <br />33. A vegetation community is termed minor if it is less than 10 acres in total, or it contributes 5 percent <br />or less to the total acreage. Meeting the lesser of these two criteria eliminates a vegetation type from <br />specific reclamation planning. <br />Revision Date: 8/5/11 <br />Revision No.: PR -03 <br />