Midwest Nut Company produces cans of mixed-nuts on a high volume assembly line. Using data of last two months, it established average and range control charts to monitor the can-weight (utilizing samples of 5 cans). The control limits of X-bar and R chart are respectively as follows:
X-bar Chart: UCL = 4.25 and LCL = 3.75 and R Chart: UCL = 1.00 and LCL = 0
A recent sample is: 3.7; 4.1; 3.8; 4.1; and 4.0.
(a) Is the process still in control? (b) Why or why not? (Show all your calculations)