Out of control p chart
1990) to produce p-charts based on the Western Electric model. We follow the four rules for identifying 'out-of-control' points as recommended in the handbook ( 'p' and 'np'. 'u' and 'c'. display — Either 'on' (default) to display the control chart, or 'off' to omit the display. label — A character vector, string array, or cell array of