CuSum V mask,
Definition of CuSum V mask:
A technique for separating meaningful data from unusual circumstances in a Cumulative Sum (CuSum) chart. The mask is a V-shaped overlay placed on the chart so that one arm of the V lines up with the slope of data points, making it easy to see data points that lie outside the slope and to determine whether these points should be discarded as random events, or treated as a performance trend that should be addressed.
Meaning of CuSum V mask & CuSum V mask Definition