Generalized Variance Chartoverview how to example data see also
Generalized Variance ChartStat > Control Charts > Multivariate Charts > Generalized Variance
The multivariate form of the S chart. You can use it to simultaneously monitor the process variability of two or more related process characteristics. For example, in a medical trial of a new drug, you can monitor heart rate and blood pressure of the participants to see if these variables jointly remain constant over the course of the treatment.
If some subgroups of n = 1 and others > 1, Minitab plots the subgroups of n = 1 as missing values.
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 a column of subscripts. 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 Gen Var Options > Estimate.