
304 Quality management for organizations using Lean Six Sigma techniques
Here, n is the number of tests, X is the measurand, and τ is the standard value. It is usually
represented as a percentage of process variance or tolerance. The signicance of this bias
in our analysis is separately deduced using the discriminatory power of t-test. The best
measurement systems are traceable to some standard. The difference between an observed
average value (i.e., the average of the values generated by the measurement system) and
the standard is bias.
Bias can be evaluated using tests to determine if there is a statistical difference between
the observed av ...