MEASUREMENT UNCERTAINTY Continued...
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| Measurement Uncertainty |
NOTE 1:
The parameter may be, for example, a standard deviation (or a given multiple of it), or the half-widthof an interval having a stated level of confidence.
NOTE 2:
Uncertainty of measurement comprises, in general, many components. Some of these components may be evaluated from the statistical distribution of the results of series of measurements and can be characterized by experimental standard deviations. The other components, which also can be characterized by standard deviations, are evaluated from assumed probability distributions based on experience or other information.
NOTE 3:
It is understood that the result of the measurement is the best estimate of the value of the measurand, and that all components of uncertainty, including those arising from systematic effects, such as components associated with corrections and reference standards, contribute to the dispersion.
2.2.4 The definition of uncertainty of measurement given in 2.2.3 is an operational one that focuses on the measurement result and its evaluated uncertainty. However, it is not inconsistent with other concepts of uncertainty of measurement, such as
👉 a measure of the possible error in the estimated value of the measurand as provided by the result of a measurement;
👉 an estimate characterizing the range of values within which the true value of a measurand lies (VIM:1984, definition 3.09).
Although these two traditional concepts are valid as ideals, they focus on unknowable quantities: the “error” of the result of a measurement and the “true value” of the measurand (in contrast to its estimated value), respectively. Nevertheless, whichever concept of uncertainty is adopted, an uncertainty component is always evaluated using the same data and related information. (See also)
