Question

1. x bar and R control Charts

A quality control inspector at the Company B has taken twenty-five samples with four observations each of the sample weight (g). The data are shown in the table. Construct x bar and R control charts for these data. Identify any out-of- control points. Assume these points (if any) are assignable. Remove them and recalculate the control limits. Construct the revised x bar and R control charts. Submit data (spreadsheet) and charts.

Comment on the validity of the revised chart?

Sample	Weight in g
	X1	X2	X3	X4
1	32	36	33	35
2	36	31	35	34
3	30	32	31	33
4	29	34	38	32
5	32	37	36	33
6	35	38	43	37
7	30	37	35	33
8	29	33	28	31
9	31	33	33	32
10	35	29	35	31
11	36	40	32	31
12	33	30	29	35
13	33	30	34	34
14	35	37	36	41
15	33	35	37	30
16	31	33	34	36
17	29	34	30	37
18	34	32	34	30
19	36	35	33	31
20	33	31	33	31
21	29	32	37	33
22	30	30	29	31
23	33	32	35	30
24	36	34	31	33
25	34	35	30	30

Answer 1