Enter historical parameters for Zone Chart

Enter the historical values for the parameters that Minitab uses to calculate the center line and zones. If you do not enter values, Minitab estimates the mean and the standard deviation from the data. If you enter only one value, Minitab estimates the other parameter from the data.

Mean

You can enter a single mean for the entire chart, or you can enter a mean for each stage. The mean is used to calculate the center line

Standard deviation

You can enter a single standard deviation for the entire chart, or you can enter a standard deviation for each stage. The standard deviation is used to calculate the zones.