Answer:
process capability index = Cpl ( lower ) = 1.20 ( A )
The process capability ratio = 1.33
Explanation:
Target value = 20
mean = 19.8
standard deviation = 0.5
upper specification limit = 22
lower specification limit = 18
The process capability index =
Cpu = [tex]\frac{22- 18}{6(0.5)}[/tex] = 4 / 3 = 1.33
Cpk ( upper ) = (22 - mean ) / 3 * std
= ( 22 - 19.8 ) / ( 3 * 0.5 ) = 2.2 / 1.5 = 1.47
Cpl ( lower ) = ( mean - 18 ) / ( 3 * 0.5 ) = ( 19.8 - 18 ) / 1.5
= 1.8 / 1.5 = 1.2
hence the process capability index is Capability index with the minimum value which is Cpl ( lower ) = 1.20 ( A )
The process capability ratio = 1.33 refer to Cpu equation