MEASUREMENT UNCERTAINTY
Measurement uncertainty is a parameter associated with the measurement result and characterizing the dispersion of values that could reasonably be attributed to the measured value.
Standard uncertainty
The standard uncertainty estimated by type A, uA is calculated by the formula
The standard uncertainty, estimated by type B, uB is calculated by the formula
Standard uncertainty is the uncertainty of the measurement result expressed as its standard standard standard deviation
Сombined standard uncertainty
The standard uncertainty of the measurement result obtained from the values of other quantities equal to the positive square root of the sum of the terms, which can be the variances or covariations of these other quantities taken with the weights characterizing the change in the measurement result under the influence of changes in these quantities.
Uc - combined standard uncertainty;
Expanded uncertainty
U-expanded uncertainty
U=kUc(y)
The extended uncertainty U is obtained by multiplying the standard uncertainty of the output value uc (y) by the coverage factor k.
Extended uncertainty is the value that determines the interval near the measurement result, within which most of the distribution of values is likely to be found, which with sufficient justification can be attributed to the measured value.
To determine the measurement uncertainty, we use the following algorithm
1.recording the measurement equation
2.amendment,the calculation of the(xi,...xm)
3.determination of measurement results y=f(xi,...xm)
4.calculation of the standard uncertainty of the I-th input value u(xi)
5.calculation of total standard uncertainty uc(y)
6.calculation of expanded uncertainty of measurements U