Calibration Standards & Regulations Flashcards
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Read the first 7 Calibration Standards & Regulations flashcards as text
What is the correct definition of 'measurement uncertainty' as used in calibration standards?
Answer: A parameter associated with the result of a measurement that characterizes the dispersion of values
Per GUM (Guide to the Expression of Uncertainty in Measurement), uncertainty is a parameter characterizing the dispersion of values that could reasonably be attributed to the measurand.
Which document provides the internationally accepted methodology for evaluating and expressing measurement uncertainty?
Answer: JCGM 100:2008 (GUM)
JCGM 100:2008, commonly known as the GUM (Guide to the Expression of Uncertainty in Measurement), provides the internationally accepted framework for uncertainty evaluation.
Under ANSI/NCSL Z540.3, what is the maximum acceptable probability that a measurement result exceeds the tolerance limits?
Answer: 2%
ANSI/NCSL Z540.3 requires that the probability of false acceptance (accepting an out-of-tolerance item as in-tolerance) does not exceed 2% per measurement.
What does the 'Test Uncertainty Ratio' (TUR) represent?
Answer: The ratio of the tolerance of the unit under test to the uncertainty of the measurement standard
TUR is the ratio of the tolerance of the unit under test (UUT) to the expanded uncertainty of the measurement process used to calibrate it.
Which of the following best describes a Type A evaluation of measurement uncertainty?
Answer: Uncertainty evaluated by statistical analysis of a series of observations
Type A evaluation of uncertainty uses statistical methods applied to a series of repeated observations, such as calculating the standard deviation of a measurement set.
What is the role of a 'reference standard' in a calibration hierarchy?
Answer: It provides a known, traceable value against which other standards or instruments are compared
A reference standard provides a traceable, known measurement value used to calibrate transfer standards or working standards, forming part of the traceability chain.
What is 'in-tolerance probability' in the context of ANSI/NCSL Z540.3 compliance?
Answer: The probability that the actual value of a measured parameter is within its specified tolerance
In-tolerance probability (or end-of-period reliability) is the probability that a parameter's true value lies within its specified tolerance limits at the time of calibration.