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1 <br />' For statistical purposes, each cover transect (comprising 50 data points) served as a <br />sample unit. Data points recorded the first vertical "hit" on vegetation, rock, soil, or <br />' litter (above or below the instrument) Subsequent "hits" were recorded to determine <br />relative cover. Cover data was recorded and reported by individual plant species. The <br />first interception was used to calculate cover values. The quantitative cover data <br />' provided the basis for calculation of species composition diversity. <br />SAMPLE ADEQUACY <br />Sample adequacy calculations were undertaken for vegetative cover sampling in the <br />' reference area and Areas 1 and 2. The following formula was used for these <br />calculations: <br />-(t)?-(s)~---- <br />nm~ _ <br />(d Xbar)Z <br />' where: non =minimum sample size <br />t =the Student's t distribution value at the 90% confidence level and <br />sample degrees of freedom <br />s =sample standard deviation (s)Z= sample variance <br />d =percent acceptable deviation from the mean (10%) <br />' Xbar =sample mean <br />Sample adequacy was achieved for vegetation cover sampling in all areas sampled. <br />' Vegetation cover was tested at the 90% confidence level. Twelve samples were taken <br />in the Upland Sagebrush Reference Area. Ten samples were taken in Area 1. Sixteen <br />' samples were taken in Area 2. <br />STATISTICAL ANALYSIS <br />' Evaluation of revegetation establishment and success was accomplished through a <br />separate comparison of each areas mean vegetative cover with the mean vegetative <br />' cover of the Upland Sagebrush Reference Area. Aone-tailed Students t test (Zar, <br />1974) was used to determine whether the mean vegetation cover of each area was <br />significantly less than 90Y6 of the reference area cover with 904'o confidence. This <br />' evaluation is consistent with that recommended by the Division of Minerals and <br />Geology in their 1988 Guidelines for Compliance with Land Use and Vegetation <br />Requirements of the Colorado Mined Land Reclamation Board for Coal Mining. <br />' Analysis of quantitative relative cover data derived from quantitative total cover <br />information provided the basis for assessment of species composition. <br />1 <br /> <br /> 6 <br />' <br />