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cover standard. If the null hypothesis is calculated using the T-test, the calculated k value is less than the table <br />t~ value and the null hypothesis is not rejected and the reclamation would be still be considered successful. <br />Null Hypothesis: H°: u ? Q <br />u= the bond release cover mean <br />Q= 90% of the approved cover standard. <br />Please refer to page 22 of the Colorado Division f Minerals and Geology Guideline Regazdin~ Selected Coal <br />Mine Bond Release Issues, dated April 18, 1995, for the T-test formula. <br />t test: t~ = Qz <br />Q = 90% of the standard <br />x =Bond release sample block mean <br />,~ =Standard error of the mean (s/ ~ ) <br />S = standazd deviation <br />n =sample size <br />t~ = calculated t value <br />Table value for t~ = 1.345. n-1 degrees of freedom for alpha error probability of 0.10. <br />t - 36.9-36.13 _ 0.2655 <br />10.86 <br />14 <br />0.2655 < 1.345 so k < t,, therefore the Null hypothesis (H°) is not rejected, and revegetation is deemed <br />successful for cover (without field bindweed included in the cover value). <br />2 <br />