Laserfiche WebLink
www.bio-geo.com <br />Standard. CDRMS regulations for Phase 3 bond release and the NH-2 permit specify the <br />standard for cover and production as the mean value for the reference area. Revegetation is <br />considered "successful" for the parameter in question if the mean value for the reclaimed area is <br />demonstrated to equal or exceed "Q" (Q=90% of the standard), at the 90% confidence level. <br />2.3 Statistical Procedures <br />Sample adequacy will be calculated using equation 1. A minimum sample size of 15 or 30 will <br />be required, depending on the comparison methodology employed, as addressed below. <br />Equation 1 1Y <br />nm = y <br />where: <br />n. = minimum sample size <br />sz = Sample variance (n-1 degrees of freedom) <br />d = Precision (0.10 for cover and production; 0.15 for woody <br />plant density) <br />z = Sample arithmetic mean <br />t = The (a=.10) t-table value for a 1 tail t-test, n-1 degrees of <br />freedom (infinite degrees of freedom may be used if n>30) <br />n = Sample size <br />Mean values for cover and production will be calculated for each study area. Mean values for <br />each post mine land use type will be compared to the standard (respective reference area <br />means) according to the general procedures described below in the Comparison of Measured <br />Parameters. rP'Ili ? do oL S Al 1d6111 L S A, /,..e -, .,,, r i ( f /,( <br />Comparison of Measured Parameters. The following summarizes CDRMS regulations and <br />guidance on comparing vegetation measurements at reclaimed lands to standards for purposes <br />of determining adequacy for Phase 3 bond release. (rec) = reclaimed area, (ref) = reference <br />area. <br />1. If sample adequacy is achieved and sample size of at least 15 is met at (rec) and (ref), <br />and if the sample mean (rec) equals or exceeds Q, then revegetation is successful. If <br />the sample mean (rec) is less than Q, then statistical hypothesis testing is required, as <br />follows. <br />2. If sample adequacy is achieved at (rec) and (ref), and the sample mean (rec) is less than <br />Q, use a one-sample "standard null" t-test (Equation 2). A one-sample test assumes <br />that the mean (ref) is a "standard" rather than a sample mean, and does not require an <br />evaluation of the variance of the mean (ref) or other statistical complications inherent in <br />two-sample tests. The null hypothesis being tested is that the mean (rec) is equal to or <br />greater than Q. If the null hypothesis is NOT rejected, revegetation is successful. <br />Equation 2 <br />5