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• procedures involved slow implementation of qualitative pedestrian transacts and careful visual scanning <br />of the ground surface for any of the target species. Although all plant spades observed within the <br />vegetation study area were identified, special attention was given to target sensitive spades within <br />appropriate hatitats. <br />2.6 Sample Adeauacv Determination <br />Within each community type sampling for ground cover and production was conducted to a <br />minimum of 15 transacts. From these initial samples, a mean and standard deviation for each variable <br />was calculated. Where statistical testing is required, collection of an adequate sample (rti111°) is typically <br />necessary to insure reliable estimates of the population (e.g., estimates tp within 10°~ of the true mean <br />(p) with 90% confidence). Altiwugh statistical testing i5 not a study requirement;, the minimum numbers <br />of samples necessary was determined to establish scientific defensibility as appropriate. The Cochran <br />formula below was utilized in accordance with directives in Cobrado's guidelines (1988). When the <br />inequality (n,M„ 5 n) is true, sampling on be considered to be adequate, and nmla is determined as <br />folbws: <br />~nin = (t zs z) ! (0.1 S )2 <br />Where: n =the number of actual samples collected with a minimum of 15 in each unit; <br />t =the value from the t distribution for 90% confidence with n-1 degrees of freedom; <br />s z =the variance of the estimate as calculated from the initial samples; <br />s =the mean of the estimate ~ okulated from the initial samples. <br />If the initial minimum number of samples in each area did not provide a suitable estimate of the <br />mean (i.e., the inequality was false), additional samples were collected until the inequality (n,,,~, 5 n) <br />became true or a maximum of 50 samples had been rcectted. The number of cover samples required for <br />sample adequacy in the four sampled areas ranged from 17 to 25. The Juniper Woodland WRDA and <br />Reference Area, as well as the Maed Shrubland WRDA, required the upper limit of 50 production <br />samples. This drcumstance reflects the low perennial production and high variability in these areas. <br />Only 35 production samples were necessary th reach adequacy in the Mbced Shrubland Reference Area. <br />Cmut Cams AssocurES, Inc. Page 7 E~ibit 5 - bowie WRDA Vegemtion Survey <br />