Knowledge

Metrology Dictionary

The complete VIM vocabulary — all numbered concepts of JCGM 200:2012 as faithful paraphrases with clause citations — plus clearly labeled practice terms from the GUM, ILAC, ISO and NIST guidance.

All A B C D E G I K L M N O P Q R S T U V W Z

All sources 172 VIM vocabulary 144 Practice & guidance 28

All disciplines 172 Calibration 14 Dimensional 3 General 19 Instruments 39 Mass 2 Pressure 1 Quality & Accreditation 11 Standards & Units 46 Statistics 13 Temperature 2 Uncertainty 22

Welch–Satterthwaite formula

The formula for estimating the effective degrees of freedom of a combined standard uncertainty from the degrees of freedom of its components — used to select a coverage factor from the t-distribution.

GUM (JCGM 100:2008) G.4 · Uncertainty

Working measurement standard

A standard used routinely to calibrate or verify instruments or systems, itself usually calibrated against a reference standard.

VIM (JCGM 200:2012) 5.7 · Standards & Units