A process that produces titanium forgings for automobile turbocharger wheels is to be controlled through use of a fraction nonconforming chart. Initially, one sample of size 150 is taken each day for twenty days, and the results shown in Table 7E.4 are observed.
(a) Establish a control chart to monitor future production.
(b) What is the smallest sample size that could be used for this process and still give a positive lower control limit on the chart?
TABLE 7 E.4
Nonconforming Unit Data for Exercise 7.4
Nonconforming
Day
Units
1
3
11
2
12
4
13
14
5
15
6
16
0
7
17
8
18
9
19
10
20
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