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Sample Adequacy. For each characteristic measured, statistical sample <br /> adequacy was calculated as shown below: <br /> nmin. _ (02 2 (S21 <br /> NO.1 <br /> where nmin. = minimum number of samples required to detect a ten <br /> percent change in the mean at a given level of confidence <br /> t = value of double-tail "t" for the degrees of freedom and <br /> desir d level of confidence <br /> s = stand d deviation of the sample population <br /> x = sample mean <br /> Results of these calc ations are shown in Table 2 for each of the three <br /> vegetation types and a ch vegetation characteristic measured. An exception <br /> to the sample adequacy requirement was made in the case of the aspen <br /> vegetation type. This type has already been extensively sampled and described <br /> in previous baseline in entory work at the Coal Basin Mine. Therefore, the <br /> Division of Mined Land�Reclamation has required only five production samples <br /> and ten cover and woody plant density samples, in lien of the normal sample <br /> adequacy requirement. <br /> RESULTS <br /> Sample adequacy was achieved in all instances for cover and production. <br /> Sample adequacy for woody plant density was not achieved on the mountain <br /> shrub type. This is due,to the extreme difficulty in counting individuals or live <br /> stems of certain specie of shrubs typical in the mountain shrub type, including <br /> snowberry, oak, rose, nd serviceberry. This kind of counting can be very <br /> subjective. In addition, this vegetation type itself is quite variable. Sample <br /> adequacy for production was achieved for this type only by clipping fifty plots, <br /> at which point the Divi ion imposes a sampling cutoff. <br /> Both the meadow and the aspen types are in good condition and quite <br /> productive. Much of the production is attributable to introduced pasture <br /> -6- <br />