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WESTERN <br /> RESOURCE <br /> DEVELOPMENT <br /> CORP. <br /> P.O. Box 467 <br /> 711 Walnut Street-Suite 200 <br /> Boulder, Colorado 8M <br /> (303)449-9009 <br /> July 2, 1981 <br /> Mr. Doug Bowman <br /> Mid—Continent Resources <br /> Box .158 <br /> Carbondale, CO 81623 <br /> Re: Confidence Levels and Vegetation Type Acreages <br /> Dear Doug: <br /> Enclosed you will find a table presenting: (1) a calculated t—value, <br /> (2) the corresponding confidence level (two—tailed) for that t—value, <br /> and (3) a calculated D—value (the % reduction detectable with 80% <br /> confidence) . These figures are given for cover and production means <br /> of all affected and corresponding reference areas. One—tailed confi— <br /> dence levels are also given for production values because we still <br /> maintain this is the appropriate statistical procedure. <br /> As you can see, there are no problems with the cover values as they <br /> _ meet all criteria of the CMLR. This is not true, however, of the <br /> production values. None of the confidence limits are within acceptable <br /> standards ( two—tailed) although three are acceptable (one—tailed <80%) <br /> and two are very close (<75%) . In all cases for these data, confidence <br /> levels should-be- greater than or equal to 80i; while D—values should be <br /> less than or equal to 10%. <br /> Our sample sizes are accordingly too small for the production data. <br /> This is, as you know, the result of an error in a published OSM version <br /> of the sample adequacy formula and past assurances that we could in <br /> fact use a one—tailed t—test (a decision subsequently reversed) . <br /> The acreages of the affected vegetation types are: Aspen Woodland <br /> 83.5 acres, Aspen Shrubland 16.6 acres, Spruce—fir Parkland 36.8 acres, <br /> Spruce—fir Forest 4.2 acres, Oak Shrubland 2.6 acres, and Riparian <br /> Woodland 2.0 acres. The total affected acreage is 145.7. <br />