280
VALUES OF Var(Put = V_ p 2 20000
, 363
Cw
Cc
260 Ff
FOR C = $100 AND $200
240
220
180 7]
160 1
120
100
1.
8
1
12
4
20
1
0
i
40
1
50
1.
60
1
70
4.
80
i
90
100
ALIQUOT Si ZE (w) IN GRAMS
Figure 4.
Approximate Values of the Variance of Average
Pu Concentrations as a Function of Aliquot Size
for a Composite Soil Sample Collected Approxi-
mately 150 ft North of GZ at NS~-201.
Suppose the purpose of the study is to estimate the average Am concentration over a defined area by randomly choosing n' soil samples from the
area and analyzing n aliquots randomly drawn from each soil sample.
Under the assumption of a simple cost function, Cochran finds the optimum
number of aliquots per field sample to be given by the equation (in our
notation)
419