Standard
uncertainties were combined using the root-sum-squares approach where, \(u_{combined}=\sqrt{u^2_{precision}+u^2_{bias}+u^2_{reference}}\) \cite{Joint_Committee_for_Guides_in_Metrology2008-qz,Taylor1994-ne}. Bias was incorporated as a component under the radical in the estimate of
measurement uncertainty, expanding the coverage interval \cite{Magnusson2008,Phillips1997}. The combined
standard uncertainty was expanded to the 95% coverage interval where, \(U_{95\%}=2u_{combined}\). Figure \ref{337028} shows the mean individual
uncertainty component’s percent contribution to the combined standard
uncertainty.