consuming to repeat the grazing and fistulated steer studies. It might be desirable, however, to conduct similar studies in other areas or to apply the results of the Area 13 studies to other contaminated sites at NTS or elsewhere. Considering the variability of the data obtained from Area 13 and expecting similar variability in another study area, how accurately can the means and standard deviations be estimated on the basis of a reasonable number of samples? Can reasonably accurate estimates of I be obtained from model of I_, an estimate of I_, and measurements of cand CS without having to carry out expensive grazing studies? To obtain preliminary answers to these and similar questions, a series of simulation studies was carried out as follows: Equation 1 was used to generate five synthetic samples (n =_100) of the vegetation ingestion rate, Is based on W = 410 + 82 kg and D = 0.48 + 0.12. These results were used as estimates of the true means (yu) and standard deviations (o). The data, given in Table 5, show little variation and good agree- ment between the arithmetic and the geometric estimates of means. Five synthetic samples of I. were based on the previously explained assumption that In Ty = 3.93866 +°1.74636. The results given in Table 6 show estimates (n = 100) ranging from about 150 to about 250 g/day, somewhat below the "reasonable" range (250 to 500 g/day) suggested by Smith (1977). Synthetic samples of C_ and C_, Tables 7? and 8, were generated by of Equation 3, the lognormal parameters given in Table 4, and the of fj indicated in Table 3. The synthetic samples of Cy indicate overall mean of 70 pCi/day (n = 500) versus 71 pCi/day expected. means of subsamples (n = 100) ranged from 67 to 73 pCi/day. means values an The Synthetic samples of C_, Table 8, exhibit similar properties; but the overall mean, 540 pci /g, was about 7 percent less than the expected value, 579 pCi/g. The final step in the simulation study was to generate synthetic samples of I based on Equation 1 and the lognormal distribution parameters obtained from the synthetic samples just discussed and summarized in Tables 5, 6, 7, and 8. The specific values of (xg + sg =u toa) were the following: xg(l1n I) 8.72942 * 0.31988 Table 7: xg(in C_) 4.05989 * 0.57563 Table 6: xg(1n I) 3.87002 + 1.77244 Table 8: xg(1n C) 6.10021 + 0.59454 + + Table 5: The pocket calculator program used to generate the synthetic samples of Toy summarized in Table 9, is described in Appendix I. The simulation estimate of I w 557 nCi/day (Table 9), is about 2.5 percent less than the estimate, 571 nCi/day, based on the arithmetic 498