Question: Refer to the Plastic Packaging case in.
(a) Make a control chart for the standard deviation of hole position. Is short-term variation stable?
(b) Make a control chart for mean hole position based on subgroup standard deviations. Is process aim stable?
(c) For each day separately, make charts for the standard deviation of hole position. Is short term variation stable for each day?
(d) For each day separately, make charts for mean hole position (use an estimate of σ based on the subgroup standard deviations). Is process aim stable for each day?
(e) For each of (a), (b), (c), and (d), was it helpful to use the subgroup standard deviations instead of the subgroup ranges as in? Why or why not?