Laserfiche WebLink
- iii iiiiiiiiniiiiii <br />ERT 999 <br />ENVIRONMENTAL RESEARCH & TECHNOLOGY, INC. <br />BOX 2105 1716 HEATH PARKWAY. FORT COLLINS. COLORADO 80522. (303) 4938878. TELEX: 45 910 ECOLCOCOR FTCN <br />RECEIVED <br />~~B 161983 <br />February 14, 1983 <br />ALINED LAND RECLAMATION <br />Mr. Dan Matthews COLO. DEPT. OF NATURAL RESOL':tCES <br />Colorado Mined Land Reclamation <br />1313 Sherman Street, Room 423 <br />Denver, CO 80203 <br />Dear Dan, <br />During your preliminary review of the Peabody Seneca 2-W vegetation <br />section, you discovered several errors in the sample adequacy and t-test <br />calculations. ERT has reanalyzed the data and corrected the errors. I am <br />enclosing corrected tables for sampling adequacy (Table 20), and the t-test <br />comparisons between reference areas and study areas for the aspen, mixed <br />brush, and sagebrush types on the mine area, and the low sagebrush, meadow, <br />and wheat types on the haul road. I have also attached a corrected formula <br />for the t-test for unequal n and unequal variances that appears in the Methods <br />section. <br />ERT greatly regrets these errors, and apologizes for the inconvenience <br />they may have caused you during your review. <br />Sincerely yours, <br />~ENV~IRO/N/h1ENTAL RESEAR`C/H & TECHNOLOGY, INC. <br />Scott L. Ellis <br />Project Manager <br />cc: V. Pfannenstiel <br />Enclosures <br />SLE:dcr <br />ATLANTA • CHICAGO • CONCORD, MA • FORT COLLINS, CO • HOUSTON • LOS ANGELES • PITTSBURGH • WASHINGTON. DC <br />