# QualityMagazine - Brain Teasers Volume 1

## Section Six: Keywords And Appendix

*2014-02-19 03:59:20*

Appendix
Control Chart Analysis for Average and Range Charts (n>1)
• Calculate the average and range of the data values in each subgroup.
• Plot the average values on one chart and the range values on another chart.
• Calculate the grand average (average of the averages) and the average of the ranges .
These are called the central lines on the two charts. Draw these lines on the charts.
• Calculate the limits on the chart for average values using the following formulas:
UCLX = X + A2R LCLX = X – A2R
• Calculate the limits on the chart for ranges using the following formulas:
UCLR = D4R LCLR = D3R
Control Chart Analysis for Individual and Moving Range Charts (n=1)
• Make a run chart of the individual data values in time order.
• Compute the moving ranges and chart them in time order.
Moving ranges are the absolute difference between adjacent data values that are in time order.
• Calculate the average of the individual values and the average of the moving ranges.
These are called the central lines on the two charts. Draw these lines on the charts.
• Calculate the limits on the chart for individual values using the following formulas:
• Calculate the limits on the chart for moving ranges using following formula:
UCLR = 3.268mR
Capability Analysis: The Technique
• Collect data from a process and plot the data over time.
• Analyze the data using a process behavior chart.
• If the process is predictable, go to the next steps. If not, work to get the process predictable.
• Make a histogram of the individual data values.
• Calculate the Natural Process Limits and mark them on the histogram to show what the current process is capable of producing.
• Mark the customer specifications on the histogram.
• Can the process meet the specifications? Calculate Cp.
• Is the process meeting the specifications? Calculate Cpk.

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