Re: G R&R ANOVA, AIAG, 6sigma Xbar/R, GM.. methods
The ANOVA and Xbar/R methods will provide similar results. The Xbar/R method is easier to calculate by hand, but if you have a computer available, the ANOVA method will provide more accurate results, including the effect of the Operator x Part interaction.
However, both methods will lead to the same decision, unless your gage is very borderline. For example, one may give you a %GRR of 30.1% while the other gives 29.9%. The results are similar, but when the cutoff point is 30% max, they will lead to different decisions.