ALTANA Auto-Chart - Manual (Page 26)

6.4 xR-Chart: The voice of the process
... records the mean and range values for several checkzones per individual car (1) and
automatically calculates the process limits. One filter per report needs to be created. At
least two checkzones need to be selected to calculate a range, usual amount of
checkzones are 4 to 10
(2) .
Example:
Typically the xR-chart checks how critical colors or high runners are performing over time.
Three reports (horizontal, vertical left and right) were defined for the color "Black":
Finished QC-Report in Excel: