4 (3 points) An EWMA chart with ?? = 0.2 and ?? = 3 is used to monitor individual observations measured in a process. The process mean and standard deviation are 10 and 1, respectively. (a) If ??4 = 12, and ??5 = 14, calculate ??5 and the control limits for ??5 (1.5 points). (b) If we want to modify this EWMA chart so that it has good detection performance for 1?? mean shift, what ?? and ?? values would you recommend? Please justify your answer based on the table provided below. (0.5 point) (c) Based on (b), keeping your selected ??, but using a smaller L, how does it affect ARL0 and ARL1 ? (just simply answer (i) increase, (ii) decrease, (iii) no change). Dose the false alarm performance and detection power become better or worse? (1 point)