Defining Variables for MEWMA (Individuals) Chart - Specs Tab

Select the Specs tab of the Defining Variables for MEWMA (Individuals) Chart dialog box to access options to specify a mean vector and/or variance/covariance matrix for the multivariate chart. If specified from this tab, these values (mean vector, and/or variance/covariance matrix) are used in the computations to construct the chart. By default, these statistics are computed from the data.

The following options are useful to specify standard values from previous charting as the standard against which to chart new samples.

Option Description
Mean vector Click Mean vector to display a General User Entry Spreadsheet. Specify the means (center line values) for the variables selected for the chart. The multivariate chart is constructed based on the means entered, instead of means computed from the data, for more details, see Multivariate QC Computational Details.
Variance covariance matrix Click Variance covariance matrix to display a General User Entry Spreadsheet. Specify here the variance/covariance matrix (sigma values) for the variables selected in for the chart. The multivariate chart is constructed based on the variance/covariance matrix entered, instead of the matrix computed from the data, for more information, see Multivariate QC Computational Details.