2017-03-10_REVISION - C1981019 (9)

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recording the variable intercepted by each of the narrowly focused (0.02') beams (Figure 1). In this manner, a total of 100 intercepts per transect were recorded resulting in 1 percent cover per intercept. This methodology and instrumentation facilitates the collection of the most unbiased, repeatable, and precise ground cover data possible. Every third sample point on the reference areas is skipped for ground cover data collection. 2.3 Sample Adeauacy Determination Sampling within each unit (reference area or Phase II area) was conducted to a minimum of 20 samples for Phase II area and 20 samples for the reference areas. From these preliminary efforts, sample means and standard deviations for total non -overlapping vegetation ground cover were calculated. For non -monitoring applications, the typical procedure is that sampling continues until an adequate sample, nmin, has been collected in accordance with the Cochran formula (below) for determining sample adequacy, whereby the population is estimated to within 10% of the true mean (N) with 90% confidence. When the inequality (n,,,in <_ n) is true, sampling is deemed adequate; and nmin is determined as follows: nmin = (t 2s 2) I (0.1 X )2 where: n = the number of actual samples collected (initial size = 20) t = the value from the one -tailed t distribution for 90% confidence with n-1 degrees of freedom; S 2 - the variance of the estimate as calculated from the initial samples; x = the mean of the estimate as calculated from the initial samples. If the initial samples do not provide a suitable estimate of the mean (i.e., the inequality is false), additional samples would be collected until the inequality (nmin <_ n) becomes true. Table SA - Sa a AdegwW Results Phase H Bond Reference Areas Moan Shrub Sagebrush Release Bkxk Mean = 51.95 55.45 51.05 Variance = 74.787 120.682 76.892 n = 20 20 20 nmin = 4.89 1 6.92 1 s.20 — Lasers utilized for this instrument are state-of-the-art and of specialized design to emit a unique electro -magnetic wavelength visible under full sunlight, a condition previously not possible with portable low-energy lasers. 8