The red triangle menu next to Average Chart contains the following options:
Show Grand Mean
Draws the overall mean of the Y variable on the chart.
Show Connected Means
Draws lines connecting all of the average measurement values.
Show Control Limits
Draws lines representing the Upper Control Limit (UCL) and the Lower Control Limit (LCL) and labels those values. The control limits for the Average Chart use the same calculations as an XBar control chart. See Control Limits for XBar and R Charts.
Show Control Limits Shading
Adds shading between the UCL and LCL.
Show Separators
Draws vertical lines to delineate between the X variables.
Show Data
Adds the data points to the chart.
Note: You can replace variables in the Average Chart in one of two ways: swap existing variables by dragging and dropping a variable from one axis to the other axis; or, click a variable in the Columns panel of the associated data table and drag it onto an axis.