To customize control limits for a C chart
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1    In the C chart dialog box, click C Chart Options. Click the Limits tab.

2    Do any of the following:

·    To specify where control limits are drawn: under Display additional sigma limits at, enter one or more values in These multiples of the standard deviation. Each value is the number of standard deviations the lines should be drawn at, above, and below the mean.

·    To set bounds on the control limits: check Lower standard deviation limit bound (and/or Upper standard deviation limit bound) and enter a value. Each value represents the number of standard deviations below and above the mean.

3    Click OK in each dialog box.