The following data represent 25 successive subgroup averages and moving averages of span size 5 of these subgroup averages. The data are generated by a process that, when in control, produces normally distributed items having mean 30 and variance 40. The subgroups are of size 4. Would you judge that the process has been in control throughout?
|
X t
|
Mt
|
X t
|
Mt
|
|
35.62938
|
35.62938
|
35.80945
|
32.34106
|
|
39.13018
|
37.37978
|
30.9136
|
33.1748
|
|
29.45974
|
34.73976
|
30.54829
|
32.47771
|
|
32.5872
|
34.20162
|
36.39414
|
33.17019
|
|
30.06041
|
33.37338
|
27.62703
|
32.2585
|
|
26.54353
|
31.55621
|
34.02624
|
31.90186
|
|
37.75199
|
31.28057
|
27.81629
|
31.2824
|
|
26.88128
|
30.76488
|
26.99926
|
30.57259
|
|
32.4807
|
30.74358
|
32.44703
|
29.78317
|
|
26.7449
|
30.08048
|
38.53433
|
31.96463
|
|
34.03377
|
31.57853
|
28.53698
|
30.86678
|
|
32.93174
|
30.61448
|
28.65725
|
31.03497
|
|
32.18547
|
31.67531
|
|
|