Question

Federal Scanline, Inc. uses a scanner on a conveyor line which scans 1,000 packages per hour. Packages which have defective labels or detectable damage to the package are automatically offloaded and hand-sorted by severity of defects, on a scale of 1-5. A minor defect is a 1, such as a single num- ber missing from a zip code. A 3 would be a mod- erate defect, such as a missing addressee name or partially missing address. A 5 would be a critical defect, such as a severely damaged package or missing address label. Construct a c-chart for the 30 samples showing critical defects from the data in the table in the worksheet Prob. 8-46 in the C08Data.xlsx file and interpret the results.

Problem 8-46
Federal Scanline
	Number of
Sample	Nonconformances
1	12
2	11
3	1
4	10
5	5
6	4
7	1
8	9
9	4
10	6
11	5
12	7
13	10
14	9
15	13
16	1
17	14
18	11
19	11
20	12
21	9
22	8
23	6
24	14
25	5
26	11
27	10
28	7
29	3
30	11
	240

Answer 1

Ans:

As all the points are within the limits, the process is assumed to be in control. We notice a saw-tooth pattern which is displayed by this control chart. To explain this, take an example, a person is trying to reach a value. If the outcome is above this value, the person makes a change to lower the value. If the result is below that value, the person makes an change to raise the value. This results in a saw-tooth pattern.

Possible reasons of the pattern could be Tampering by operating person or More than 1 process is there (shifts, raw materials).