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Statistical Methods <br />i <br />I • <br />STATISTICAL DESIGN . <br />Cover and herbaceous production data were collected in all areas. Production data and woody <br />plant density data were collected in the 2002 and 2004 Reclaimed Areas, but were not collected <br />in any of the reference areas, nor in the Phase II bond release sampling. Sampling proceeded <br />using a single stage statistical design. <br />Sample locations in reclaimed areas were randomly plotted by use of an internal script routine <br />within ArcView software. Minimum spacing between sample points was 170 feet (one 50 m <br />transect length). The SCC-assigned number of samples for a given parameter in a given area <br />reflected previously experienced sample variability or the level of precision required for that area. <br />In the extended reference areas, each reference unit was gridded and numbered. Grid cell size <br />was 200 feet X 200 feet. These grid cells were placed contiguously by hand on maps of 1:4,800 <br />scale. Sample locations were selected as the center points of grid cells selected using random <br />numbers generated by computer. <br />Sample points were located in the field using topographic maps. Cover and woody plant density <br />transects were located and oriented using a blind throw of a meter stick. The final location of <br />each herbaceous production plot was chosen with a blind throw of the sampling hoop made from <br />the origin of the associated cover/woody plant density transect. At each cover/woody plant <br />density sampling location, the slope (percent) and aspect of the site were determined and <br />recorded, as was the orientation of the transect (in degrees not corrected for magnetic <br />declination). <br />SAMPLE ADEQUACY CALCULATIONS <br />Sample adequacy calculations for parameter estimation without hypothesis testing were carried <br />out using the formula as prescribed by the Colorado Mined Land Reclamation Board for . <br />parameter estimation without hypothesis testing (CDMG 1995): <br />~z Sz <br />Nmin --------- <br />(d X )z <br />Where: <br />to =one-tailed t-value with (n-1) degrees of freedom, a=0.10 <br />4 <br />