Key points are not available for this paper at this time.
SUMMARY The use of a V-mask on a cumulative sum chart is shown to be equivalent to the simultaneous operation of two single-sided schemes with horizontal decision boundaries. A method for obtaining the average run length (A.R.L.) of a V-mask is derived and some values are given from which a number of masks can be constructed with known values of the A.R.L.’s at two specified quality levels.
Kenneth W. Kemp (Sun,) studied this question.