Question: Refer to the Paper Dry Weight case in. Recall that the target for dry weight of 20- lb bond paper is 70 g/ m2. The pump speed controlling the flow of liquid pulp mixture onto the conveyor-roller mechanism was held fixed at 4.5 (45 % of maximum flow) in the production of the data in problem 38. Assume that under stable process conditions, dry weights are normally distributed. The dry weight of a sample was recorded for each of 12 consecutive samples, approximately equally spaced in time
(a) Find control limits to apply to the data of. Use the nominal dry weight of 70 as a target value, and employ MR¯/1.128 as an estimate of σ. Does the process appear to be stable? Why or why not?(b) 100 measurements correspond to how many subgroups in the context of
(c) Suppose that the limits of (a) are applied to the future monitoring of individuals. About what ARL is produced if σ is as in part (a), but μ increases from its standard value by 3.5 g/ m2? Assume the process is stable and dry weights are normally distributed.
(d) If completely retrospective control limits were used (x was used in place of the target value for dry weight), would your conclusion in (a) change? Why or why not?