Interpretation & Calculations
A Process Capability Index. A measure of both process dispersion and its centering about the average.
Znormal,p and Znormal,1-p are the z-values of the normal cumulative distribution curve at the p percentage point and the 1-p percentage points, respectively.
Learn more about the SPC principles and tools for process improvement in Statistical Process Control Demystified (2011, McGraw-Hill) by Paul Keller, in his online SPC Concepts short course (only $39), or his online SPC certification course ($350) or online Green Belt certification course ($499).