Answer:
1. The Cpk of machine 1 would be 0.952
2. The Cpk of machine 2 would be 1.111
3. I would buy machine 2, because the Cpk value is more than 1.
4. The Cpk would be 2.222
Explanation:
1. In order to calculate the Cpk of machine 1 we would have to use to following formula:
Process capability index: Cpk= Min [(mean-L spec)/3sd; (U spec-mean)/3sd]
According to given data:
In machine 1, mean= 48mm
L spec= 46
U spec= 50
Standard deviation sd= 0.7
Therefore, Cpk of machine 1= [0.952;0.952]= 0.952
1. In order to calculate the Cpk of machine 2 we would have to use to following formula:
Process capability index: Cpk= Min [(mean-L spec)/3sd; (U spec-mean)/3sd]
According to given data:
In machine 2, mean= 47
L spec= 46
U spec= 50
Standard deviation sd= 0.3
Therefore, Cpk of machine 2= [1.111;3.333]= 1.111
3. If my goal is to be capable, I would buy machine 2, because the Cpk value is more than 1.
4. If you combine the best of both machines to calculate the cpk we to make the following calculation:
Combination specification, mean= 48 and L spec= 46 and U spec= 50, Standard deviation sd= 0.3
Therefore, Cpk= [2.222;2.222]= 2.222
