Dictionary · Uncertainty
Output quantity in a measurement model
The quantity whose measured value is calculated from the input quantity values using the model — the measurand's seat in the mathematics.
Related terms
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Coverage interval
The interval containing the set of true quantity values of a measurand with a stated probability, based on available information — unlike a classical confidence interval, not necessarily centred on the measured value.
VIM (JCGM 200:2012) 2.36
Triangular distribution
A probability distribution rising linearly to a peak midway between limits ±a. Used when values near the centre are more likely; its standard uncertainty is a/√6.
GUM (JCGM 100:2008) 4.3.9
Coverage factor
The number k by which a combined standard uncertainty is multiplied to obtain an expanded uncertainty; k = 2 is standard certificate practice, with a t-based k when effective degrees of freedom are small.
VIM (JCGM 200:2012) 2.38
Coverage probability
The probability that the set of true quantity values of a measurand is contained within a specified coverage interval — commonly 95 % in calibration practice.
VIM (JCGM 200:2012) 2.37
Type B evaluation of measurement uncertainty
Evaluation of a component of uncertainty by means other than statistical analysis of current measurements — calibration certificates, specifications, handbook data, assumed distributions.
VIM (JCGM 200:2012) 2.29
Relative standard measurement uncertainty
A standard uncertainty divided by the absolute value of the measured quantity value — the form specifications and CMCs often quote (parts in 10⁶, percent of reading).
VIM (JCGM 200:2012) 2.32