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4.1 Quality and Uncertainty in the Measurement Laboratory

Carroll Croarkin

Keith Eberhardt

Mark Levenson

Lynne Hare

Statistical Engineering Division, CAML

Norman Belecki

Electricity Division, EEEL

Concepts of quality, measurement assurance, and uncertainty analysis for metrology were brought together in a one-day workshop presented at the ASQC Measurement Quality Division Conference in Rockville, MD on April 22-23, 1996. Belecki began the discussion by explaining the relationship between a measurement assurance approach which relies upon statistical control for assuring the quality of measurements and uncertainty analyses which are used for quantifying the goodness of measurements. He also explained the role of check standards in the measurement laboratory. Croarkin outlined the NIST policy on uncertainty and worked through a case study that illustrated the use of check standards and auxiliary experiments for estimating type A components of uncertainty. Levenson followed with a discussion and case study of type B components of uncertainty and the procedure for combining type A and B uncertainties by propagation of error techniques. Eberhardt concluded the uncertainty discussion by dealing with the difficult problem of uncertainties of measurements corrected by linear calibration. In a wrap-up session, Hare demonstrated statistical thinking as a tool for achieving quality in all scientific investigations.

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Date created: 7/20/2001
Last updated: 7/20/2001
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