The measurement uncertainty in the calibration of a thermometer depends on the calibration method used, the uncertainty contri

u_{bath s}: Temporal stability: important characteristic of a bath is also short-term stability of a medium temperature. It strongly depends on type of regulation and flow of medium inside the bath. Since the calibration measurements are taken within short time interval, the short-time stability is relevant. For the time stability of a bath, temperature deviations of a reference thermometer are observed.

Example:

5. 
   Combined standard uncertainty
   

The combined standard uncertainty of a measurement result is taken to represent the estimated standard deviation of the result. It is obtained by combining the individual standard uncertainties ui, whether arising from Type A or Type B evaluation.

The quantity u_i (i = 1, 2, …, N) is the contribution to the standard uncertainty associated with the output estimate y resulting from the standard uncertainty associated with the input estimate as described in sections 2.1 to 2.4.

The calculation of the degrees of freedom drives the uncertainty analysis in terms of confidence. The greater the degrees of freedom the higher is confidence in the parameter. The degrees of freedom are used to calculate the coverage factor.

Calibration laboratories should state an expanded uncertainty of measurement U, calculated by multiplying the standard uncertainty u_c(y) by a coverage factor k.

Quantity	Brief description	Correction	Standard uncertainty	Distribution	Sensitivity coefficient	Uncertainty contribution
Tr, uTra	Standard deviation	0 K	2 mK	normal	1	2 mK