Question: A manufacturing process produces bags of cookies. The distribution of weights of these bags should have a mean of \(\mu \) = 15.0 oz. and a standard deviation of \(\sigma \) = 0.4 oz. In order to monitor the process, four bags are randomly selected and their mean weight, \(\bar{X}\), is determined. These values of \(\bar{X}\) are plotted on an Xbar control chart.

Give the upper control and lower control limits for this control chart.