Define the Statistics Region
Statistics are taken from a region defined on the curve by range boundaries, which are defined by two points on the selected curve.

To select the minimum and maximum values of the region, do one of the
following:
Two vertical lines are displayed, representing the minimum and maximum values of the region.
 Once the range boundaries have been specified, click Calculate to compute the curve statistics for the defined area. Each time the range markers are moved, the statistics need to be recalculated.