MEASUREMENT UNCERTAINTY
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| Measurement Uncertainty |
Measurement Uncertainty is the expression of the statistical dispersion of the values attributed to a measured quantity.
Uncertainty means the range of possible values within which the true value of the measurement lies.
Uncertainty (of measurement): parameter, associated with the result of a measurement, that characterizes the dispersion of the values that could reasonably be attributed to the measurand.
The parameter may be, for example, a standard deviation (or a given multiple of it), or the half-width of an interval having a stated level of confidence.
Definition 1:
Uncertainty of measurement comprises, in general, many components. Some of these components may be evaluated from the statistical distribution of the results of a 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.
Definition 2 :
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.
Definition 3:
Standard uncertainty: uncertainty of the result of a measurement expressed as a standard deviation
Definition 4:
Type A evaluation (of uncertainty): method of evaluation of uncertainty by the statistical analysis of series of observations
Definition 5:
Type B evaluation (of uncertainty): method of evaluation of uncertainty by means other than the statistical analysis of series of observations.
