Cartons of Plaster are supposed to weigh exactly 32 ounces. Inspectors want to develop process control charts. They take five samples of six (6) boxes each and weigh them. Sample means (X-bar) are:...

Extracted text: Cartons of Plaster are supposed to weigh exactly 32 ounces. Inspectors want to develop process control charts. They take five samples of six (6) boxes each and weigh them. Sample means (X-bar) are: 33.8, 34.6, 34.7, 34.1, and 34.2 respectively. Also, the corresponding ranges are: 1.1, 0.3, 0.4, 0.7, and 0.3, respectively. The lower and upper control limits of the xbar-chart are respectively O a. 33.12 and 34.12 b. 34.01 and 34.55 O c. 30.11 and 40.15 O d. None is correct O e. 37.01 and 39.23