Dictionary · Uncertainty
Measurement uncertainty
A non-negative parameter characterizing the dispersion of the quantity values being attributed to a measurand, based on the information used — the quantitative expression of doubt about a result.
Related terms
More from Uncertainty
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
Measurement model
The mathematical relation among all quantities known to be involved in a measurement, of the general form f(Y, X₁, …, Xₙ) = 0.
VIM (JCGM 200:2012) 2.48
Combined standard measurement uncertainty
The standard uncertainty obtained from the individual standard uncertainties (and covariances) of the input quantities through the measurement model — root-sum-of-squares in the uncorrelated case, denoted u꜀.
VIM (JCGM 200:2012) 2.31
Input quantity in a measurement model
A quantity that must be measured, or whose value can be otherwise obtained, to calculate a measured value of the measurand.
VIM (JCGM 200:2012) 2.50
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