Options - Stages
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Charts  All charts except Z-MR

You can display stages in your process by drawing a "historical chart" - a control chart in which the control limits and center line are estimated independently for different groups in your data. Historical charts are particularly useful for comparing data before and after a process improvement.

Note

With the following charts, you must have at least one subgroup with two or more observations: R,  S,  X and R, and X and S.

Dialog box items

Define stages (historical groups) with this variable: Enter the column that contains the stage indicators.

When to start a new stage

With each new value: Choose to start a new stage each time the value in the column changes.

With the first occurrence of these values: Choose to start a new stage at the first occurrence of a certain value, then enter the values. Enclose date/time or text entries in double quotes. You can enter the same value more than once; Minitab treats each repeated value as a separate occurrence.