Modify the options for I-MR Chart (Options tab)

On the Options tab of the Individuals Chart dialog box, specify the mean or standard deviation and specify observations to exclude.

Parameters

The mean and standard deviation are used to calculate the center line and control limits. You can have Minitab estimate these parameters from the data or you can enter historical values. If you enter only one historical value, Minitab estimates the other parameter from the data.

Estimate the mean and standard deviation from the data
Estimate the parameters from your data.
Specify the value for one or both parameters
  • Mean: Enter a single mean for the chart. Minitab uses the mean to calculate the center line on the I chart.
  • Standard deviation: Enter a single standard deviation for the chart. The standard deviation is used to calculate the control limits on both charts and the center line on the MR chart.

Omit observations from the estimation of parameters

If some observations have erratic data because of special causes that you have already corrected, you can omit these observations from the calculations to avoid incorrect parameter estimates.

In Omit the following observations when estimating parameters (optional), enter the observations. Use a colon to indicate a range of observations. Leave a space between each observation or range of observations. For example, to specify observations 4, 7, 11, 12, 13, and 14, enter 4 7 11:14.

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