After you have changed the display range, you can display statistics for just that range.
To show statistics for a display range:
Set the display range as described in Focusing On the Display Range.
In the forecast chart menubar, choose Preferences, then Forecast, then Filter.
On the Filter tab of the Forecast Preferences dialog, set a filter on the forecast values and include values in the range between the display range minimum and maximum.
Choose View, then Statistics in the forecast chart menubar to show statistics for the display range (or, in Split View, look at the statistics table).