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Process performance indices

Process performance indices use sigma of the individuals .


pp formula

Pp for one-sided specifications

If you are using one sided specifications, use the following formulas to determine the Cp:

Upper specification:

ppu formula

Lower specification:

ppl formula


ppk formula


Zmin is the smaller of Zupper and Zlower.

Using sigma of the individuals:

z upper formula

z lower formula


pr formula

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