Use the x-bar R control chart to monitor and improve processes where data can be collected at about the same time and/or under similar conditions.
The chart will display the variation between the sets of data, called subgroups, in the x-bar section and between the individual observations in the R section.
This way, the x-bar section shows how the process being measure changes day after day, while the R section shows how much the data is changing each day.
Both parts of the chart filter out the random noise existent in all processes so that signals to action may be identified.
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