With the above in mind, the following approach was used in selecting the number of sample locations per stratification (group, island, portion of island): i. The planning would be based on the soil concentrations of Plutioniun-239, 2. A coefficient of variation with a value of 0.7 was assumed based on the review of previous soils data and the presumed conditions from the ranking of islands, historical reports, etc., previously discussed. 3° The standard error was expressed in terms of the assumed coefficient of variation and the mean soil concentration value. Confidence limits, the probable error (PE) which is taken as two standard errors were thus expressed as a proportion of the mean: SE = standard error =, yn where: 6 is the standard deviation nis the number of samples in the specific area being in- c = coefficient of variation = 6, x . vestigated (number). . ARI mete where: x is the,mean concentration value of the samples collected for the specific area being investigated (mean). Putting 6 in terms of c: 6 = cx. Substituting this into the standard error: SE=6 yn = cx. Yn Expressing the standard error as a proportion of the mean, x? SE, = SE = x ex =e. yn & Yn" Defining the confidence limits as the probable error (PE), equal to 2 standard errors, 2 SE, and setting it as a proportion of the mean, xX, the PE, would be 2 SE, : PE, = © SE, = 2c yi and the mean, x, with these confidence limits would become: x + 2c jn