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Uncertainty Files for Standards

Calibration Executive 4.0 Help

Edition Date: March 2017

Part Number: 374564H-01

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Calibration Executive stores uncertainty information for common standards, including calibrators and DMMs, in tab-delimited text files under the Calibration Executive\Uncertainty directory. Calibration Executive prompts you to select whether to include uncertainty information when you run a procedure. The Calibrator Uncertainty Information dialog box, shown in the following figure, displays the list of calibrators for which Calibration Executive has uncertainty files. You can select a calibrator from the displayed list, or you can browse to select another uncertainty file.

The DMM Uncertainty Information dialog box displays the list of DMMs for which Calibration Executive has uncertainty files. You can select the DMM model you are using from the displayed list, or you can browse to select another uncertainty file.

Each uncertainty file contains a confidence level that corresponds to a coverage factor, as listed in the following table. These coverage factors assume an infinite number of degrees of freedom.

Confidence Levels and Corresponding Coverage Factors
90%95% 95.45% 99%99.73%
1.645 1.960 2.000 2.576 3.000

Note Note   For a more detailed table of confidence levels and coverage factors, refer to Annex G in ANSI/NCSL Z540–2-1997, U.S. Guide to the Expression of Uncertainty in Measurement.

Related Topics

Uncertainty Files for Commonly Used Standards


 

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