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• Sample Adequacy A summary of sample adequacy calculations for the parameters of cover, herbaceous production and woody plant stem density is presented in Table 12 (Appendix 1). As can be seen in Table 12, sample adequacy was achieved or nearly achieved for all cover sampling, was close to being achieved for herbaceous production sampling only in the Sagebrush Reference Area, and was achieved for shrub density only in the two-stage sampling of shrub density in the Wadge Pasture. In accordance with atwo-stage statistical design, the Wadge Pasture was equally divided into twenty primary sample units of approximately 15 acres each (Map 1); of the twenty primary units, fifteen were randomly chosen for sampling. Fifteen was chosen as a sample size that was short of expending the effort to sample everything, yet would provide an ample number upon which to calculate variance. Within each primary unit, three (3) 2mx50m shrub density transects were randomly located and randomly oriented in the normal fashion. The sampling fraction of the primary units (n/N) was 15/20. The sampling fraction within each primary unit (m/M) was 3/607, that is, within each 15 acre primary unit, there was a potential to have 607 • different sample locations, of which three were actually sampled. Variance was calculated in the fashion described in Cochran (1977: expression 10.14) and the Methods section above (terms used in the expression below are defined in the Methods section). 1-t, 1-fZ V~ S,Z + SZa n mn 1-(15/20) 1-(3/607) VY = 33.54 + 19.30 = 0.985 15 3 x 15 The result of sample adequacy calculation using the above calculated variance (0.985) was that with a sample size of fifteen (the number of primary units), the minimum sample size required (using atwo-tailed t-value with fourteen degrees of freedom: t=1.761) was nine. Thus, • the use of a two-stage sampling approach allowed the achievement of sample adequacy with 22