Select the analysis options for Nonnormal Capability Analysis for Multiple Variables

Stat > Quality Tools > Capability Analysis > Multiple Variables (Nonnormal) > Options

In This Topic

Targets
Use tolerance of K × σ for capability statistics
Display

Targets

To specify target values for your process variables, enter one value, multiple values, or a column of values. If you enter one value, it applies to all variables or groups. If you enter multiple values or a column of values, the values correspond sequentially to the columns that you entered in Variables or to the groups in the By variables column.

If you enter target values, Minitab displays a target value on the capability histogram and the process data table for each variable or group.

Use tolerance of K × σ for capability statistics

Enter the width of the tolerance in number of standard deviations (σ). By default, the tolerance is 6 standard deviations wide (3 standard deviations on each side of the process mean).

You can enter one value, multiple values, or a column of values. If you enter one value, it applies to all variables or groups. If you enter multiple values or a column of values, the values correspond sequentially to the columns that you entered in Variables or to the groups in the By variables column.

Minitab interprets the K value as the width of a two-sided tolerance. If you want to use a one-sided tolerance, enter a two-sided tolerance value that is twice that of the one-sided tolerance. For example, if you want to use a one-sided tolerance of 3σ, enter 6.

Note

If you want the tolerance value that you enter to be the default setting for every capability analysis that you perform, choose File > Options > Control Charts and Quality Tools > Capability Analysis and enter the default tolerance.

Display

Select the measures of capability that you want Minitab to display:

Capability stats (Pp): Calculate and display capability statistics such as Pp.
Benchmark Z’s (σ level): Calculate and display Z.bench values. The choice to use Z.Bench often depends on company or industry practices.

Select how you want to display the expected and observed out-of-specification values:

Parts per million: Display the values in parts per million (PPM).
Percents: Display the values as percentages.

Note

If you want to change which statistics display by default, choose File > Options > Control Charts and Quality Tools > Capability Analysis and change the default display setting.