- You have been given the following data from a new process. You are required to establish if the process is in control and if so calculate the process mean and control limits. Plot the trial control chart.
Order of data collected Measurement 1 Measurement 2 Measurement 3
1 6.91771 7.05203 7.13381
2 6.96658 6.97857 6.96948
3 6.99659 7.05730 6.97309
4 7.12885 6.84270 6.89206
5 7.05266 7.02656 6.90942
6 7.03477 7.10764 7.12563
7 6.99418 7.00990 6.89035
8 6.90271 7.00616 6.97185
9 7.05016 6.97908 7.10476
10 7.02785 6.97049 6.97710
11 7.12771 7.03482 6.90100
12 7.06852 7.03464 6.94801
13 6.93516 6.98386 6.96217
14 7.21037 6.88932 7.05895
15 7.04732 6.94565 7.04844
16 6.88890 7.01776 6.95527
17 7.02779 6.81799 6.83689
18 7.03468 7.09038 7.04646
19 6.99739 7.00265 7.03186
20 6.95768 6.90034 6.89950
21 6.92173 7.02207 7.09677
22 7.05358 6.88721 6.92090
23 7.07646 7.05165 6.96647
24 6.96376 6.91121 7.09154
25 7.00708 7.05864 7.05622
26 6.91974 6.81374 6.96462
27 7.00878 6.98672 7.11000
28 6.89346 7.10918 6.99019
29 6.94766 6.94900 6.87517
30 6.93886 7.03697 7.01349
- Plot the following set of data on the trial control chart using the already calculated mean and control limits. Is the process still in control? Discuss your observations and evaluation. Is any action required? If so explain.
Order of data Measurement 1 Measurement 2 Measurement 3
31 7.11853 6.85876 7.17237
32 6.85000 6.89000 6.84120
33 7.15990 7.03559 6.80185
34 7.04850 7.11347 7.05841
35 7.06474 7.00233 7.00111
36 7.10706 7.04572 6.85982
37 7.06469 6.90171 7.10187
38 6.92408 6.92328 7.13582
39 7.03288 7.14053 6.99103
40 7.00905 6.92497 6.90965
41 6.90800 7.00917 6.97658
42 6.99413 6.99610 7.05182
43 7.09216 7.13009 7.20741
44 6.92791 7.13377 7.02761
45 7.15012 6.93249 6.80982
46 7.06462 6.96993 7.03912
47 6.90386 6.98100 6.96052
48 6.95892 7.01865 7.09756
49 6.97042 6.96925 6.88985
50 6.95328 7.00599 6.87680
51 7.12985 7.00809 7.16017
52 6.99120 6.85778 7.00225
53 7.08490 7.01361 7.04337
54 7.05439 7.05925 7.13183
55 7.07673 6.93206 7.12090
56 6.95537 7.05203 7.04220
57 7.10212 7.00674 6.89203
58 6.97293 6.96722 7.07965
59 6.90674 7.00964 7.07586
60 7.15539 7.14770 6.93264
61 6.75736 6.97322 6.86419
62 7.10103 7.06919 6.89317
63 7.17920 6.94467 6.99145
64 7.03337 6.99729 6.86333
65 6.97335 7.08364 6.98468
- Explain when to set the process control limits in this case.
- How confident are you that the customer will be happy with parts from this process? Explain your answer.
Customer specification: 7.00+/-0.20. - This is not a critical variable for the component that is being measured. How do you recommend controlling this variable for the longterm.