QC-CALC's CPK is different than my manual calculation
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written: 02/01/2006
last modified: 03/26/2024


How are the calculated values I see in the lower left corner of each Real-Time plot calculated? I get a different value when I manually calculate Cpk.


You are probably using a different set of numbers in one location to calculate Cpk than you are in the other location. All calculations are based on visible data, so having the same data set is crucial in getting the same Cpk value.


The lower left corner of each plot contains a calculated result. This number gives you immediate feedback of each feature’s current situation. All calculations are based on the visible data not older, off-screen values. You may choose several calculated values; Average, Avg & Range, Cpk, Cp, Cr, Sigma, Range, P/T Ratio, Cmk, or the Last Value Received. Note that a calculation is not displayed on a Scatter plot.

Applies To

GageStation v.4.10
GageStation v.4.00
GageStation v.3.40
QC-CALC Enterprise for Gage v.3.00
QC-CALC Real-Time v.4.10
QC-CALC Real-Time v.4.00
QC-CALC Real-Time v.3.40
QC-CALC Real-Time v.3.00
QC-CALC SPC v.4.10
QC-CALC SPC v.4.00
QC-CALC SPC v.3.40
QC-CALC SPC v.3.00
QC-Gage v.4.10
QC-Gage v.4.00