2.
Measurement Process Characterization
2.3. Calibration 2.3.3. What are calibration designs? 2.3.3.3. Uncertainties of calibrated values


Standard deviation of test item depends on several factors 
The final question is how to combine the repeatability standard
deviation and the standard deviation of the check standard to estimate
the standard deviation of the test item. This computation depends on:


Derivations require matrix algebra 
Tables for estimating standard deviations for all test items are
reported along with the solutions for all designs in the
catalog. The use of the
tables for estimating the standard deviations for test items is
illustrated for the 1,1,1,1 design. Matrix
equations can be used for deriving estimates for designs that are
not in the catalog.
The check standard for each design is either an additional test item in the design, other than the test items that are submitted for calibration, or it is a construction, such as the difference between two reference standards as estimated by the design. 