Reproducibility Sigma Chart Calculations

Note: This chart is used when Number of Appraisers > 10

Plotted Statistic:

The sample standard deviation of Appraiser averages for each part, calculated using the average for the plotted part (x-barpc)

Center Line:

The average of the plotted statistic

Control Limits:

where S-bar is the Center Line (above) and c4 is based on a subgroup size m = the number of Appraisers.

Note: Some authors, including AIAG, refer to the quantity (1+3(SQRT(1- c4^2))/c4)) as B4 , and (1-3(SQRT(1- c4^2))/c4)) as B3

See also:

Reproducibility X-Bar Chart Calculations

Reproducibility Range Chart Calculations

Learn more about the Quality Improvement principles and tools for process excellence in Six Sigma Demystified (2011, McGraw-Hill) by Paul Keller, or his online Green Belt certification course ($499).