What is the appropriate control chart that can be used by

Question

Question: Workers at a packaging operation shovels a granular product from a large pile into sacks that are then sealed and placed on pallets for shipping. A sequence of 25 subgroups each consisting of the weights of 5 sacks has been recorded as follows:

	Observations
Subgroup #	Sack 1	Sack 2	Sack 3	Sack 4	Sack 5
1	35.4	35.6	34.8	34.7	34.8
2	36	35.6	34.9	34.8	35.9
3	35.2	35	35	35.4	35.1
4	34.8	35.8	35.2	35	34.9
5	34.2	35	36.1	34.9	35.1
6	36	35	35.2	34.8	34.9
7	36.1	34.9	34.5	35	35.1
8	35.1	35	35.6	34.9	36.2
9	35	35.6	36.1	34.8	35.6
10	35.4	35.8	36	34.2	36
11	35.2	35.3	35.2	35.9	34.8
12	35.9	36	35.1	35.1	35.6
13	35.2	35.6	35	34.9	35
14	35.2	35.6	35.8	35	35.1
15	34.9	34.8	35	35.2	34.9
16	35.2	35.3	35.2	35.6	35.1
17	35.6	35.8	35.2	35.4	34.9
18	35.2	35.6	35.4	35.6	35.2
19	34.7	34.9	35.6	35.2	35
20	35	35.1	35.6	35	35.1
21	35.6	35	35.8	35.2	34.6
22	34.9	35.1	35.6	35	35.2
23	35.9	36	35.2	36	35.2
24	35.2	35.1	35.4	34.9	35.1
25	35.2	35.2	35.1	35.6	34.9

a- What is the appropriate control chart that can be used by the quality engineer in this case?

b- Determine the control limits (show your calculations)

c- Construct the appropriate control chart for the data above using MINITAB.

d- Is the process in-control? If not, when does the out-of-control behavior occur?

e- If the process is found to be out of control, drop the out-of-control points and use MINITAB to re-construct the control chart.

f-  Is the process now in-control? If not, what to do next?