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. Mr. Mike Savage ~ • <br />Colorado Mined Land Reclamation Division <br />May 23, 1983 <br />Page 3 <br />where z = the number of standard deviations of the difference <br />between zr and xm <br />s2 = estimated variance for the data from the reference <br />r areas (a pooled estimate for all three reference <br />areas) <br />sm = estimated variance for the data from the re vegetated <br />area <br />n = total number of exclosures sampled on the reference areas <br />r <br />n = total number of exclosures sampled on the re vegetated area <br />m <br />Again, if the calculated z exceeds 1.283, the null hypothesis would be rejected and <br />a conclusion of failure reached. As mentioned for cover evaluations, success is <br />indicated without hypothesis testing when xm ) .9 xr. <br />Irrespective of the procedure approved by the Division, Trapper proposes judging <br />success from weighted averages as described in section 4.4.1 pages 4-101 and 102, <br />of Trapper's permit application. <br />Please apprise us of the Division's preference for the analytical procedure [o use. <br />As previously discussed, we feel that none of the existing concepts for evaluating <br />re vegetation success have been proven valid. Should additional data indicate the <br />selected procedure is based on an incorrect concept, an alternative procedure will <br />be developed or proposed for the Division's approval. <br />Please contact me if there are any questions. <br />Sincerely, <br />Wayne E. Sowards <br />Assistant to the Mine Manager <br />Trapper Mine <br />WES/js <br />cc: J. T. Atkins <br />D. L. Humphreys <br />R. L. Fanyo <br />H. G. Morris <br />Dave Shelton, ChD.RD~ <br />Administrator, OSM Western <br />Technical Center <br />file <br />