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Gage R&R Study (Nested)ANOVA Method |
The Gage R&R output shows how the total variability is divided up among the following sources:
Ideally, very little of the variability should be due to repeatability and reproducibility; instead, differences between parts (Part-to-Part) should account for most of the variability. This would be shown by:
The most important information is found in the %Contribution, %Study Var, %Tolerance, and %Process columns. These columns show the sources of variation. Typically, the Total Gage R&R should equal less than 30% of the study variation, and less than 10% would be ideal.
If you entered a process tolerance or a historical standard deviation, then either the %Tolerance or the %Process column may be more important than %Study Var.
Example Output |
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Total Gage R&R 7437.38 86.33 Repeatability 7437.38 86.33 Reproducibility 0.00 0.00 Part-To-Part 1177.55 13.67 Total Variation 8614.93 100.00
Process tolerance = 500 Historical standard deviation = 87.3786
Study Var %Study Var %Tolerance %Process Source StdDev (SD) (6 × SD) (%SV) (SV/Toler) (SV/Proc) Total Gage R&R 86.2403 517.442 92.91 103.49 98.70 Repeatability 86.2403 517.442 92.91 103.49 98.70 Reproducibility 0.0000 0.000 0.00 0.00 0.00 Part-To-Part 34.3154 205.892 36.97 41.18 39.27 Total Variation 92.8167 556.900 100.00 111.38 106.22 |
Interpretation |
For the temperature data, the Total Gage R&R equals 92.91% of the study variation. This means that almost all of the variability in the temperature measurements is due to either the gage or the operators. It appears as if some corrective action should be taken. This action may include training of operators or acquiring better gages.
Free online chart generators for statistical analysis:
Useful tools: