Design of Experiments Guide > Prospective Sample Size and Power > Sigma Quality Level Calculator > Statistical Details for the Sigma Quality Calculator
Publication date: 04/12/2021

Statistical Details for the Sigma Quality Calculator

Calculations for the sigma quality calculator are based on the definition of sigma quality level σq for d defects in n opportunities:

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From this definition, d and n can be calculated as follows:

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where Φ() is the standard normal cumulative distribution function and Z1-d/n is the (1 - d/n)th quantile from the standard normal distribution.

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