. Author manuscript; available in PMC: 2011 Mar 1.

Published in final edited form as: Anal Chem. 2010 Mar 1;82(5):1942–1948. doi: 10.1021/ac9026862

Table 3B.

Estimation of Expanded Uncertainties for LC-MS/MS Measurements of Serum 25(OH)D₂

	Conc (ng/g)
Mean	0.857
Type A
Standard deviation	0.017
Standard deviation of mean	0.006
Type B
1 % Uncertainty of systemic error	0.009
0.15 % Uncertainty of purity of reference compound	0.001
0.1 % Uncertainty of weighing	0.001
Combined standard uncertainty (u_c)	0.010
Coverage factor (k)	2
Expanded uncertainty (U)^a	0.021
Relative expanded uncertainty, %	2.4

95 % confidence interval.