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Publication date: 06/21/2023

Sigma Quality Level

Use the Quality Explorer for Sigma Quality Level to explore relationships between the number of defects, number of opportunities for defects, and the Sigma Quality Level. The Sigma Quality Level is a statistic that relates a given defect rate to a six-sigma scale. For example, a defect rate of 3.4 per one million opportunities results in a six-sigma process. Select DOE > Sample Size Explorers > Quality > Sigma Quality Level.

Quality Explorer for Sigma Quality Level Profiler

The profiler enables you to visualize the impact of sample size assumptions on the sigma quality level calculations.

Solve for

Enables you to solve for the number of opportunities or defects.

Sigma Quality Level

The defect rate in standard deviation units.

Number of Opportunities

The number of opportunities for a defect.

Number of Defects

The number of defects.

Quality Explorer for Sigma Quality Level Options

The Explorer red triangle menu and report buttons provide additional options:

Simulate Data

Opens a data table of simulated data based on the explorer settings. View the simulated response column formula for the settings used.

Make Data Collection Table

Creates a new data table that you can use for data collection. The table includes scripts to facilitate data analysis.

Save Settings

Saves the current settings to the Saved Settings table. This enables you to save a set of alternative study plans. See Saved Settings in the Sample Size Explorers.

Help

Opens JMP help.

Statistical Details for the Quality Explorer for Sigma Quality Level

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

Equation shown here

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

Equation shown here

Equation shown here

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.

Want more information? Have questions? Get answers in the JMP User Community (community.jmp.com).