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selected as the center points of grid cells selected using random numbers generated by computer. In <br />2013, sample points number 1 through 10 generated in 2008 for each reference area were used as <br />sample locations. <br />Sample points were located in the field using Garmin GPS 60 handheld units and topographic maps. <br />Cover and woody plant density transects were oriented using, at a glance, the seconds reading on a <br />wristwatch x 6 as an azimuth or a blind spin of a meter stick. The final location of each herbaceous <br />production plot was chosen with a blind throw of the sampling hoop made from the origin of the <br />associated cover /woody plant density transect. At each cover /woody plant density sampling location, the <br />slope (percent) and aspect of the site were determined and recorded, as was the orientation of the <br />transect (in degrees not corrected for magnetic declination). <br />Statistical Methods <br />Sample adequacy calculations (for informational purposes only) for parameter estimation were carried out <br />using the formula as prescribed by the Colorado Mined Land Reclamation Board for parameter estimation <br />without hypothesis testing (DMG 1995): <br />2 <br />t � S 2 <br />00 Nmin= <br />(d x )2 <br />where: <br />t„ = one - tailed t -value with (n -1) degrees of freedom, a =0.10 <br />s2 = sample variance <br />d = 0.1 (0.15 for woody plant) (level of precision or desired detectable reduction) <br />x = sample mean <br />Confidence Limits <br />Confidence limits for comparisons to reference areas and technical standards were calculated using a 1- <br />tailed t -value for alpha error probability of 0.10 at (n -1) degrees of freedom multiplied by the standard <br />error of the mean of the sampled area. <br />000C. I. = t s <br />Un <br />4 <br />