Capability indices

Capability indices use estimated sigma .

Cp

Cp for one-sided specifications

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

Cr

Cpk

Where:

Zmin is the smaller of Z_upper and Z_lower.

Using estimated sigma:

Cpm

Where:

T = specification target (nominal)

Xi = a given individual reading of " i "

n = total number of individual readings

= symbol for summation