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 Table 2. Example of Method Evaluation and Uncertainty Budget Evaluation experimental results The following are results from a simplified evaluation of a specific diffusive sampler for oxylene. There were four experimental runs with four samplers each. The reference concentration set within the exposure chamber is denoted as B) relative uncertainty = 1%.

Run 1

(ppm) = 123

replicates (ppm) 139.2 138.2 138.6 145

Run 2

(ppm) = 101.1

(ppm) = 12.7

(ppm) = 91.3

14.0%

1.8%

9.2%

7.9%

12.2%

2.1%

17.8%

replicates (ppm) 14.2 15.3 12.9 14.6

Run 4

2.6%

replicates (ppm) 108.3 110 110.7 112.8

Run 3

having an assigned (Type

replicates (ppm) 109 109.2 107.1 105

Averaging the above bias estimates and pooling the inter-sampler estimates Mean bias estimate: biâs = 13.3% from average of 4 × 4 = 16 data points. The TRSD estimate is

3/15/03

results in:

having 4 × 3 = 12 degrees of freedom.

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NIOSH Manual of Analytical Methods