Supplement - Page 3.

Note:

These computations assume the data are homogeneous, i.e. there are
no trends in the data.

Since there are trends present on Janet

(increasing concentrations near GZ areas) these kinds of computations should be done separately for GZ and low level areas.
Ill.

One-Sided Confidence Limit on a Proportion

Using "Attribute Sampling" by Herman Burstein, Mc-Graw-Hill, 1971,
(Table 1) we can obtain the following probability statement:
The probability is 100(1-a) that the proportion of soil samples

with Pu concentrations greater than or equal to the cleanup
Level L is less than or equal to P.

Estimates of P for various values of a for cleanup level 40pCi/g

(using

the 139 soil samples (0-15 cm) from Janet) are:
a

0}

. 167

.10

. 133

.05

Interpretation:

P
145

Note:

Proportion of samples with Pu
concentrations 2 40 pCi/g is

13/139 = .0935.

For a = .01;
We are 99% sure that 16.7% of the soil samples on Janet
have concentrations 2 40pCi/g.

Discussion:

A possible approach to deciding whether an island needs to be

cleaned up is as follows:

The island (or parts of the island)

will be cleaned up unless P is Tess than, say, 5% for some
specified a level, say .01.

If it had happened that only 1

of the 139 samples had a Pu concentration 2 40pCi/g then we find

that P = .047 (4.7%) for a = .01.

Hence, in that hypothetical

case we would decide not to cleanup the island if the above

rule (P <.05 when a = .01) had been used.

An alternative and

perhaps preferable method of deciding whether cleanup is necessary is discussed under Question 3, part B.

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