Example of Attribute Gage Study (Analytic Method)
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An automobile manufacturer wants to measure the bias and repeatability of an automated attribute measurement system. The system has a lower tolerance of -0.020 and an upper tolerance of 0.020. The manufacturer ran 10 parts, which had reference values at intervals of 0.005 from -0.050 to -0.005, through the gage 20 times.

1    Open the worksheet AUTOGAGE.MTW.

2    Choose Stat > Quality Tools > Gage Study > Attribute Gage Study (Analytic Method).

3    In Part numbers, enter Part number.

4    In Reference values, enter Reference.

5    Click Summarized counts and enter Acceptances. In Number of trials, enter 20.  

6    Click Lower limit and enter -0.020. Click OK.

Graph window output

Interpreting the results

The bias in the attribute gage system is 0.0097955, and the adjusted repeatability is 0.0458060. The test for bias indicates that bias is significantly different from 0 (t = 6.70123, df=19, p = 0.00), suggesting that bias is present in the attribute measurement system.