The Attribute Gage Study examines the precision of a measurement system when measurement is binary. It calculates the amount of bias and repeatability of the measurement system.
1. Choose ProcessMA > Quality Tools > Gage R and R > Attribute Gage Study.
2. In Part, select the column containing the part indicators.
3. In Reference, select the column containing the reference values or known standards.
4. In Summarised counts, select the column containing summarised data.
5. In Trials, enter the number of trials.
6. In Tolerance limit to use, choose if you want to use the lower limit or upper limit and enter a value for the tolerance level.
Optional
7. In Test bias=0 method, choose if you want to use the AIAG method or the Regression method to test the bias of the gage.
Note To select a column of data into a textbox, double-click on any of the column names shown in the list on the left of the dialog box while in the textbox.
Part: Text or Numeric.
Reference: Numeric. Must contain equal number of data points as the Part.
Summarised counts: Numeric.
Trials: Integer; Greater than zero.
Tolerance limit: Numeric.
You want to determine the bias and repeatability of an attribute (pass/fail) measurement system. You measured 10 parts of different reference values, 15 times each. You know that the system has a lower tolerance of 0.2 and an upper tolerance of 1.0.
1. Open worksheet ProcessMA > Tools > Data Files > Gage.xls.
2. Choose ProcessMA > Quality Tools > Gage R and R > Attribute Gage Study.
3. In Part, select H – PartA.
4. In Reference, select I – ReferenceA.
5. In Summarised counts, select J – AcceptanceA.
6. In Trials, enter 15.
7. In Tolerance limit to use, choose lower limit and enter 0.2.
8. Click OK.
Interpretation
The bias and repeatability is shown in the output. The p-value for the test for bias is 0, suggesting that bias is present in the measurement system.