14 A special cause can result from 1 point one points of any group of three points outside the +/- 2 stdev interval from the centerline but on the same side of the centerline two points of any group of three points outside the +/- 3 stdev interval from the centerline but on the same side of the centerline two points of any group of three points outside the +/- 1 stdev interval from the centerline but on the same side of the centerline two points of any group of three points outside the +/- 2 stdev interval from the centerline but on the same side of the centerline