MiniTab includes the insignificant interaction Term Operator x Part in the final calculation of %GAGE R&R.
Attached I have an EXCEL ANOVA GRR Calculation for the same data's which I put into Minitab.
If you stay with alpha 0.25 to remove the insignificant interaction term Operator x Part the Results differ from Minitab. (even though MiniTAb Session Window stated to remove the Interaction Term also at alpha 0.25)
If you manipulate alpha to 1 in my Excel Sheet to INCLUDE the insignificant OPxPart Interaction --> everything is fine.
But this is wrong !
Ok it differs not much but unfortunately these Values are used to callibrate the Outcome from other Statistical Software.
And therefore some People who trust MiniTab would say my EXCEL Calculation is somehow wrong.