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I• until: 1) a minimum of 15 samples have been collected and 2) sampling adequacy (nm;,J has been <br />attained in accordance with the promulgated Colorado guideline (April 18, 1995) formula for sample <br />adequacy when statistical testing is not required, as follows. <br />Rmin=(t 25~/(O.lx~ <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 from 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) would be utilized for troth reclaimed and reference areas to increase the <br />statistical power of the test. This formula is: <br /> <br />where: n =the number of actual samples collected with a minimum of t5 in each unit; <br />~ = the value from the single tailed t distribution for a = 0.1 with n-1 degrees of <br />freedom; <br />tp =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 />z =the mean of the estimate as calculated from the initial samples. <br />According to the approved permit, once an adequate sample has been collected for both the <br />revegetated community and the extended reference area for both cover and production, the means and <br />variances (x and s2) 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 />• <br />~s~aa 3~ ~s~c~vas, Inc Page 9 Horn, ilwmpnon creek Mmes worse u a io 9ond rmressa eveluetlon <br />