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Question 10.8: Compute the process capability index for each process in Exa......

Compute the process capability index for each process in Example 7.

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The specification width in Example 7 is .80 mm. Hence, to determine the capability index for each process, divide .80 by the process width (i.e., six standard deviations) of each machine. The results are shown in the following table:

We can see that only process B is capable because its index is not less than 1.33. (See Figure 10.15 for a visual portrayal of these results.)

Process Standard Deviation (mm) Process Capability C_{P}
A .13 .78 .80/.78 = 1.03
B .08 .48 .80/.48 = 1.67
C .16 .96 .80/.96 = 0.83
figure 10.15

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