T2
and Generalized
Variance Chartoverview how to data example see also
T2
and Generalized
Variance ChartStat > Control Charts > Multivariate Charts > Tsquared-Generalized Variance
The T2 and generalized variance chart is the multivariate counterpart to the Xbar-R, Xbar-S, and I-MR charts. You can use this chart to simultaneously assess whether the process mean and variation are in control.
Minitab draws the T2 chart in the upper half of the display; the generalized variance chart appears in the bottom half. Because Minitab displays both charts together, you can track the process level and process variation simultaneously. You can also detect the presence of special causes.
For more information, see Control Charts Overview and Multivariate Control Charts Overview.
Variables: Enter at least two columns of data.
Subgroup sizes: Enter a number or column of subscripts. If the subgroups are not equal, each control limit is not a single straight line but varies with the subgroup size. If the subgroup sizes do not vary much, you may want to force the control limits to be constant by specifying a fixed subgroup size using Tsq-GV Options > Estimate.