Answer:
The Cpk of this line is 0.6667.
Step-by-step explanation:
Cpk:
In a process with mean [tex]\mu[/tex], standard deviation [tex]\sigma[/tex], upper limit U and lower limit M, the CPK is of:
[tex]C_{pk} = \text{min}(\frac{U-\mu}{3\sigma}, \frac{\mu-L}{3\sigma})[/tex]
Average of 61 psi with a standard deviation of 2 psi.
This means that [tex]\mu = 61, \sigma = 2[/tex]
The specification calls for the acceptance range to be from 55 psi to 65 psi.
This means that [tex]L = 55, U = 65[/tex].
Cpk
[tex]\frac{U-\mu}{3\sigma} = \frac{65-61}{3(2)} = 0.6667[/tex]
[tex]\frac{\mu-L}{3\sigma} = \frac{61-55}{3(2)} = 1[/tex]
The minimum of these values is 0.6667, so the Cpk of this line is 0.6667.
