Design specifications require that a key process for reviewing claims is 210 3 minutes. A process being considered for reviewing claims has a standard deviation of 0.516 minutes.

What can you say (quantitatively) regarding the process capability if the process mean is centered (i.e., equal to the spec mean)? Calculate the Cp and interpret it.

4.2

Suppose the process average shifts to 208.5. Calculate the new process capability (Cpk).

4.3

What can you say about the process after the shift? Is it more or less capable? Is it capable? (Interpret the new Cpk in item 4.2)

4.4

To achieve four sigma quality (i.e., Cp = 1.33), what should be the process standard deviation if the process mean is centered?

n	A2	D3	D4
2	1.88	0.00	3.27
3	1.02	0.00	2.57
4	0.73	0.00	2.28
5	0.58	0.00	2.11
6	0.48	0.00	2.00
7	0.42	0.08	1.92
8	0.37	0.14	1.86
9	0.34	0.18	1.82
10	0.31	0.22	1.78
11	0.29	0.26	1.74
12	0.27	0.28	1.72
13	0.25	0.31	1.69
14	0.24	0.33	1.67
15	0.22	0.35	1.65
16	0.21	0.36	1.64
17	0.20	0.38	1.62
18	0.19	0.39	1.61
19	0.19	0.40	1.60
20	0.18	0.41	1.59