One could look at this standard as a target circumference

Question

Baseball circumferences. Baseballs used in the major leagues in the United States must adhere to strict stan- dards. One such standard is that the circumference must be between 9 and 9.25 inches. One could look at this standard as a target circumference of 9.125 inches with a tolerance of +> - 0.125 inches. These data (shown at the bottom of the page) were taken from a random sample of 50 baseballs from a large production batch. The actual circumference and deviation from the target circumference are listed.

Using the specification limits as the control limits,

a) Create a run chart for the baseballs' circumferences.

b) Is the process for making baseballs in terms of their circumference in control?

c) How many baseballs produced were out of spec?

d) When should the quality team have investigated the production process?

Sample	Circumference	Deviation	Sample	Circumference	Deviation
1	8.998	- 0.127	26	9.121	- 0.004
2	9.181	0.056	27	9.111	- 0.014
3	9.147	0.022	28	9.130	0.005
4	9.182	0.057	29	9.116	- 0.009
5	9.087	- 0.038	30	9.035	- 0.090
6	9.154	0.029	31	9.188	0.063
7	9.108	- 0.017	32	9.092	- 0.033
8	9.109	- 0.016	33	9.078	- 0.047
9	9.141	0.016	34	9.101	- 0.024
10	9.093	- 0.032	35	9.113	- 0.012
11	9.142	0.017	36	9.087	- 0.038
12	9.140	0.015	37	9.054	- 0.071
13	9.125	0.000	38	9.177	0.052
14	9.175	0.050	39	9.058	- 0.067
15	8.985	- 0.140	40	9.179	0.054
16	9.119	- 0.006	41	9.147	0.022
17	9.140	0.015	42	9.123	- 0.002
18	9.109	- 0.016	43	9.097	- 0.028
19	9.190	0.065	44	9.108	- 0.017
20	9.087	- 0.038	45	9.214	0.089
21	9.046	- 0.079	46	9.140	0.015
22	9.108	- 0.017	47	9.151	0.026
23	9.188	0.063	48	9.041	- 0.084
24	9.125	0.000	49	9.061	- 0.064
25	9.114	- 0.011	50	9.162	0.037