Data considerations for Generalized Variance Chart

To ensure that your results are valid, consider the following guidelines when you collect data, perform the analysis, and interpret your results.

Multiple variables are correlated

If variables are not correlated, use R Chart, S Chart, or Moving Range Chart.

The data should be continuous

If your data are counts of defectives or defects, use an attribute control chart, such as P Chart or U Chart.

The data should be in time order

Because control charts detect changes over time, the order of the data is important. You should enter the data in the order it was collected, with the oldest data at the top of the worksheet.