A manager wishes to build a control chart for a process. A total of five () samples are collected with six (06) observations within each sample. The sample means (X-bar) are15.36, 14.61, 16.36, 20.28...

A manager wishes to build a control chart for a process. A total of five () samples are collected with six (06) observations within each sample. The sample means (X-bar) are15.36, 14.61, 16.36, 20.28 , and 15.77 respectively. Also, the corresponding ranges are 0.79, 8.37, 4.81, 8.17 and 3.31 respectively. The lower and upper control limits of the x-bar chart are respectively aNone is correct b. 18.5513.47 , 11.47 d. 12.60.20.36 13.07 , 19.88