CCQM-K143

MEASURAND   Mass fraction of copper in calibration solutions

NOMINAL VALUE 10 g/kg

Degrees of equivalence represented by D_i and its expanded uncertainty U_i at a 95 % level of confidence, both dimensionless.

CLOSER VIEW

CCQM-K143

MEASURAND   Mass fraction of copper in calibration solutions

NOMINAL VALUE 10 g/kg

Degrees of equivalence represented by D_i and its expanded uncertainty U_i at a 95 % level of confidence, both dimensionless.

CCQM-K143 is a model 2 comparison, for which each participating institute prepared a copper calibration solution with a target mass fraction of (10.0 +/- 0.1) g/kg and sent aliquots of the prepared solution to the pilot laboratory for comparisons with aliquots sent by all the other participants.  The participants were not told to prepare a solution of exactly 10 g/kg, but only to declare to the pilot lab what they thought their copper mass fraction values were.  The pilot laboratory compared the solutions and their declared copper mass fractions on a relative basis only.  No KCRV could be established; the KCRV was necessarily very close to 1, with no units.  In essence, if a participant's degree of equivalence is acceptable, it means that they were able to prepare the solution they stated within the uncertainty with which the pilot laboratory could perform the experimental evaluation.

CCQM-K143

MEASURAND   Mass fraction of copper in calibration solutions

NOMINAL VALUE 10 g/kg

The key comparison reference value x_R and its associated standard uncertainty u_R are obtained using a DerSimonian-Laird estimator of the relative sensitivity values S_i for qualified participants as explained on page 14 of the Final report.

        x_R = 1.00001     u_R = 0.00020

The degree of equivalence of laboratory i relative to the key comparison reference value x_R is given by a pair of terms, both dimensionless:

D_i = (S_i - x_R) and its expanded uncertainty U_i at a 95 % level of confidence.

CCQM-K143

MEASURAND   Mass fraction of copper in calibration solutions

NOMINAL VALUE 10 g/kg

x_i   measured value submitted by laboratory i, Lab_i

u_i   combined standard uncertainty of x_i

S_i        relative sensitivity value for participant's measured solution

u (S_i ) standard uncertainty of S_i

Note 1 : These results were submitted by each participant as claimed mass fractions and uncertainties based on gravimetric preparation. 
These solutions were measured as part of CCQM K143, and these values should be used to assess the validity of uncertainties of any related CMC claims.