# Gabriel Gómez

## Forum Replies Created

Viewing 2 posts - 1 through 2 (of 2 total)
• Author
Posts
• #202368

Gabriel Gómez
Participant

you do not need P to perform the calculation, the approximation assumes that if the size of the sample is large enough, it will approach normal …

0
#202260

Gabriel Gómez
Participant

The Sigma level with DPMO is a approximation to normal distribution from binomial distribution; according with central limit theory, its due to the DPMO measure the number of trials and success (%) in each sample or success (%) in the Critical characteristic of the part. Remember that a part could have many opportunities to evaluate (CTQ’s).

Example : Suppose that we have a process with this characteristic:
Example:
Units/shift = 30,000
Defective parts = 300
Defects observed = 350
Opportunities = 15
Dpu = 350/30,000 = .011
DPMO = (.011/15) x 1,000,000 = 777
Yield : 1-(0.011/15) = 99.9922%
ZBench : 3.164 *From normal distribution tables
Sigma Level: 4.664
CPk Process: 1.55

0
Viewing 2 posts - 1 through 2 (of 2 total)