approximate a logarithmic sequence to the base 2.) The mean and standard deviation of In 8.5, 1n 57.3, and In 278 are 3.9387 + 1.7464. To estimate the magnitude of a "reasonable estimate” based on these three measurements, the log mean and standard deviation were used to generate a synthetic sample (n = 500) of Ts: The individual values based on In I, = 3.9387 + 1.7464 ranged from 2 g/day to 3,575 g/day; the overall mean (n = 500) was 213 + 609 g/day. Plutonium Concentrations in Vegetation and Soil The concentrations of plutonium (pCi/g) in vegetation and soil samples collected from Area 13 are listed in Tables 1 and 2. The areas of sampling strata are given in Table 3. The arithmetic (normal) and geometric (lognormal) estimates of population parameters for each sampling stratum are given in Table 4. The raw data of Tables 1 and 2 and their natural logarithms were used to construct normalized histograms in which the cell width on the horizontal axis is_determined by z = (x-xg)/sg, where x is the limit between two cells, xg is the mean, and sg is the standard deviation of the sample set. The vertical height of the cell is the number of variates (frequency of observations) that fall in the cell interval divided by the total number of variates (n) in the sample. To facilitate comparison, a normal curve, i.e., ¢(z) = (s(2m)1/2)-1 exp (-1/2 22), was sketched on the same coordinates. The histogram (not shown) for c,1,2), the concentrations (Table 1) of plutonium in vegetation samples from strata 1 and 2, was sharply skewed to the right, suggesting a lognormal distribution, while the histogram of ln c.1,2) was sharply skewed to the left, suggesting a truncated lognormal distribution. Maps of Area 13 sampling strata (see the article by Delfiner, and Gilbert, this volume) show that parts of strata 1 and 2 extend beyond the fenced area and were not sampled. In other words, the apparently truncated distribution curve appears to be a true reflection of the actual situation. The histogram of In Cc(1-5), Figure 2, is not perfectly symmetrical, but the observed cell counts (5, 17, 35, 21, 17, 9) are close to the counts expected for a normal curve (5.3, 16.5, 29, 29, 16.5, 5.3). A chi square test, comparing the observed and expected cell counts, indicated x2 = 3.1547 and P(x2) = 0.3239. As P(x2)> 0.95 is required for rejection of the null hypothesis, the test provides no basis for rejecting the hypothesis that the observed frequency distribution is lognormal. The same procedure was followed in constructing and testing all the histograms shown in Figures 1 through 8. In no case did the chi square test indicate that rejection of the null hypothesis was required. Based on the results displayed in Figures 2, 3, 4, and 5, it was assumed that Cy and C_ are lognormally distributed in each of the six sampling strata of the inner compound. The population parameters for each sam- pling stratum (xg and sg) are given in Table 4. 488