A quality engineer collected process data for five subgroups with each subgroup consisting of four samples (n=4). The averages and ranges of samples in each subgroup are summarized in Table 2 below. The upper specification limit (USL) of the process is 13.10 and the lower specification limit (LSL) is 12.90. Table 2. Subgroup Data Subgroup 1 2 Average X 13.00 12.97 Range R 0.06 0.04 3 12.96 0.03 4 12.98 0.04 5 12.99 0.03 (2-1) Calculate the average # of subgroup averages X. Answer (average of subgroup averages) (2-2) Calculate the average R of subgroup ranges R. Answer R (average of subgroup ranges R) (2-3) Calculate the estimate of population standard deviation. Answer a (estimate of population standard deviation) (2-4) Calculate the process capability index Co. Answer