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D EPAR[MENT Or NATURAL RE SOUaCE$ • <br />D. !dome Poscoe, f+ecuiwe Dn ectm <br />ni iw i~,i~ i.,»» li 1':1:1,1\)11/1'I~II )1V <br /> <br />c <br />June 12, 1981 <br />TO: Brian Munson and Sue Mowry <br />FROM: Mike Savage~AwL~f+~- <br />RE; Responses to P.A.R. Statistics Questions by ff-G <br />Our File No. C-003-80 <br />Brian and Sue, <br />I have reviewed David Duba's responses to the statistical questions I <br />presented in my February 1I, 1981 memo. I will discuss them below in the format <br />in which they appear on the amended blue pages. <br />9.15.7(3)(b) <br />The Division has not previously accepted one-tailed t valun_s for determination <br />of sample adequacy. Ifowever, most of the Colorado mines have not utilized <br />the W,D,F..Q. sample adequacy Formula which incorporates a factor of 2 into <br />the equation. Out of curiosity, Z performed a comparison of the following <br />values and formulae: <br />For Woody Plant Communities <br />423 Centennial f3utld mg. 1313 Sherman $Ireel <br />Denver. COIOraU0 80203 7e1. (303) 839.3567 <br />David C. Shelton <br />Director <br />H-G Formula <br />_ 2(s.t)2 <br />nmin (dx <br />• • where t = 0.84 (one-tailed t at 80o confidence) <br />Acceptable Division Formula <br />_ (s t)2 <br />nmin (d-x)~ <br />where t = 1.282 (two-tailed t at 80y confidence) <br />Preferred W.D.E.Q. Formula <br />__ 2(s t)2 <br />nmin (dx <br />where t = 1.282 (two-tailed t at 80~ confidence) <br /> <br />