Fluke Digital Multimeter - Page 51

©Fluke Calibration 2011 Basics Of Measurement Uncertainty for DMM Calibration 51
Welch-Satterthwaite formula
• is the overall effective
degrees of freedom for the
combined uncertainty (u
c
).
• The formula considers each
uncertainty, each sensitivity
coefficient and each
uncertainty’s specific value
for degrees of freedom to
calculate











N
i
i
ii
c
eff
v
xuc
yu
v
1
44
4
)(
)(
v
eff
v
eff