sampling stage (sampling stage 8) is calculated as CRL1 =8.......\..., which is not greater than L=8...\.. (or CRL1 , L\...). Thus, at sampling stage 8, the first out-of-control signal is detected. Subsequent out-of-control signals are detected at sampling stages 11. 12 and 16 as CRL2, CRL3\\..\ and CRL\...\ are 3, 1 and 4, respectively, where all are less than L=8.\\...\ Actions should be taken to investigate and remove the assignable causes that lead to these out-of-control signals