A quality analyst desires to construct the sample mean chart for controlling the packaging procedure. He knows from past experience that the procedure standard deviation is two ounces. Each day last week, he randomly selected the four packages and weighed each. The data from that activity appears below.
a) Evaluate the upper and lower control limits for both sample means and ranges.
b) Is this process in control? Describe a simple Yes or No is insufficient.
c) What additional steps should the quality assurance team acquire?