2.
Measurement Process Characterization
2.5. Uncertainty analysis 2.5.6. Uncertainty budgets and sensitivity coefficients
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Example of uncertainty budget for three components of temporal uncertainty |
An uncertainty budget that illustrates several principles of
uncertainty analysis is shown below. The reported value for a
test item is the average of \(N\) short-term measurements where
the temporal components of uncertainty were estimated from a
3-level nested design with
\(J\) short-term repetitions over \(K\) days.
The number of measurements made on the test item is the same as the number of short-term measurements in the design; i.e., \(N = J\). Because there were no repetitions over days or runs on the test item, \(M = 1; \, P = 1\). The sensitivity coefficients for this design are shown on the foregoing page. |
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Example of instrument bias | This example also illustrates the case where the measuring instrument is biased relative to the other instruments in the laboratory, with a bias correction applied accordingly. The sensitivity coefficient, given that the bias correction is based on measurements on \(Q\) artifacts, is defined as \(a_4 = 1\), and the standard deviation, \(s_4\), is the standard deviation of the correction. |
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