Plastic covers for DVDs must be manufactured with enough precision so that a DVD can properly fit into the cover. Specifically, the diameter of the central plastic piece over which the DVD is placed must not vary more than a certain amount. A manufacturer has been producing DVD covers for several months and has had no complaints from its customers. It decides to use the past 2 months of data to estimate the mean and standard deviation of the process. Are the limits for quality monitoring based on these quantities control or specification limits? Explain.