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• Colorado guideline (April 18, 1995) formula for sample adequacy when statistical testing is not required, <br />as follows: <br />nmin = (t2S 2) / (0.1 X <br />Where: n =the number of actual samples collected with a minimum of 15 in each unit; <br />t =the value from the t distribution for 90% confidence with n-1 degrees of freedom; <br />s 2 =the variance of the estimate as calculated from the initial samples; <br />x =the mean of the estimate as calculated Trom the initial samples. <br />If, for an unexpected reason statistical testing is required, the sampling adequacy equation for this <br />circumstance ("Hypothesis Testing Based Sample Size Formula for Reclaimed Areas" as detailed in the <br />Colorado Guidelines -page 20) should be utilized for both reclaimed and reference areas to increase the <br />statistical power of the test. This formula appears as follows: <br />nmin = ((~ +tB ~s 2) / (0.1 Q~ <br />where: n =the number of actual samples cellected with a minimum of 15 in each unit; <br />to =the value from the single tailed t distribution for a = 0.1 with n-1 degrees of <br />freedom; <br />to = the value from the single tailed t distribution for a = 0.25 with n-1 degrees of <br />freedom; <br />s 2 =the variance of the estimate as calculated from the initial samples; <br />Q = 90% of the reference area sample mean x or 90% of the technical <br />standard <br />x =the mean of the estimate as calculated from the initial samples. <br />Axording to the approved permit, once an adequate sample has been collected for each <br />revegetated community and the extended reference area for both cover and production, the means and <br />variances (x and sZ) will be utilized for testing revegetation success or failure during that particular year, <br />if testing is necessary. Testing is not necessary if the revegetated area's mean is equal to or greater than <br />90% of the extended reference area's mean for the same variable, in which case the area passes for that <br />variable and year. (Colorado considers the reference area sample mean to be the "standard" <br />Though 2000 collected data indicated that testing is not necessary, the Applicant has chosen to <br />implement the One Sample -Reverse Null Hypothesis Testing procedure (or "bioequivalence procedure") <br />6.l~AIR d'@~ ~Q70A'Il'6®, rvc. Page 8 North Thompson Creek Mines Phase II 8111 Bond Release Evaluation <br />