Mean = sum of obs/ no of obs Mean = 347/40 = 8.6 SD = sum of square of diff/no o
ID: 390844 • Letter: M
Question
Mean = sum of obs/ no of obs
Mean = 347/40 = 8.6
SD = sum of square of diff/no of obs
SD = 28.44/40 = 0.711
Cp = (USL – LSL)/ 6 sigma
USL =11.0
LSL =5.0
Cp = (11-5)/6(0.711)
Cp = 0.001
If Cp is less than 1 process variation exceed specification and hence significant number of defects are made.
Cpk = (USL-Mean)/3 sigma or (Mean – LSL)/ 3Sigma which ever is lower
Cpk = (11- 8.6)/(3*0.711) or (8.6-5)/(3*0.711)
Cpk = 1.12 or 1.69
Cpk = 1.12
Since Cpk is less then 1.33 process is not capable
(C) No, the process is not capable of producing 3 Sigma
Since Cp is less than 1 management should focus on process variability.
BONUS QUESTION (optional): Notice all of the samples fall within the customer’s specifications of 8.0 ± 3.0. How does this make sense considering your answer to Part 2 (C)?
Explanation / Answer
Answer: