Question

Q5. Sampling of 90 retainer rings are examined for the fraction non-conforming. The results for thirty consecutive days are given below:

Day	Fraction non-conforming
1	0.12
2	0.09
3	0.03
4	0.08
5	0.14
6	0.06
7	0.17
8	0.14
9	0.15
10	0.17
11	0.15
12	0.14
13	0.13
14	0.02
15	0.09
16	0.15
17	0.17
18	0.07
19	0.03
20	0.12
21	0.12
22	0.12
23	0.09
24	0.08
25	0.02
26	0.03
27	0.15
28	0.13
29	0.16
30	0.13

Using Minitab, construct the appropriate control chart to investigate if the there is a state of statistical control with respect to the fraction non-conforming.

Answer 1

The control chart is:

The process is in a state of statistical control with respect to the fraction nonconforming.

The control limits are:

Sample size	90
Number of samples	30
	Proportion defective
Upper Control Limit, UCL	0.2066
Center	0.1083
Lower Control Limit, LCL	0.0100

Please give me a thumbs-up if this helps you out. Thank you!