Shown below is the statistics definitions window. This window appears when you select the "statistics" button in the workspace window or in the graph window. The statistic that will be computed is added to whatever subpopulations are currently selected (workspace window) or displayed (in the graph window).  Select multiple populations in the workspace to add the same statistics to all of them at once.

Once you have added statistics to a node, the easiest way to compute these statistics for other samples or subpopulations is to drag the nodes and drop them onto the desired destination.  You may also drag statistic nodes into the Layout Editor to create a text box with the statistic value, that is updated whenever the statistic itself changes value (for example, in response to your moving a gate).  Statistics are most conveniently collected and exported using the Table Editor.

You may view a complete Definition of these statistics.