Use Xbar Chart to monitor the mean of your process when you have continuous data in subgroups. Use this control chart to monitor process stability over time so that you can identify and correct instabilities in a process.
The process variation must be in control before you assess the process center using a Xbar chart because the control limits for the Xbar chart are calculated using the within-subgroup variation. If the process variation is not in control, then the Xbar chart control limits are not reliable and Minitab might produce a false out-of-control signal. Use an R or S chart to assess whether the process variation is in control.
To create an Xbar chart, choose .