The viscosity of a chemical product is read every two minutes. Some data from this process are shown in Table 10E.11 (read down, the across from left to right).

(a) Is there a serious problem with autocorrelation in these data?
(b) Set up a control chart for individuals with a moving range used to estimate process variability. What conclusion can you draw from this chart?
(c) Design a CUSUM control scheme for this process, assuming that the observations are uncorrelated. How does the CUSUM perform?
(d) Set up an EWMA control chart with = 0.15 for the process. How does this chart perform?
(e) Set up a moving center line EWMA scheme for these data.
(f) Suppose that a reasonable model for the viscosity data is an AR(2) model. How could this model be used to assist in the development of a statistical process-control procedure for viscosity? Set up an appropriate control chart, and use it to assess the current state of statistical control.

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TABLE 10E.11 Chemical Product Viseosity 29.330 9.980 27 000 24.24) 7.080 33.660 30.580 26500 23.950 264102270 2.170 28.580 30.760 30520 29.200 34.200 19.000 L030 2.630 33,560 28.080 21.280 21.710 21 40 24.710 06.250 ฐ0.550 9.350 33.600 18.500 28.190 20.110 36 540 35.700 3C8 25.230 31.790 17.790 24.220 27.630 29.890 28.180 29.290 30.280 26.140 19030 24 340 3E 530 31.950 31.680 29.100 23.150 26.740 32.440 29.390 25430 の.030 0.010 0.800 28.120 1 450 6.61030.560 30.610 29000 28.480 32.0I0 31 830 31.720 29090 31.920 31.400 30.930 31.530