Interpreting the results
Session Window Output
· Look at the p-value for the Part*Subcomponent interaction in the ANOVA Table. When the p-value for an interaction is > 0.25, Minitab omits this from the full model. Notice there is an ANOVA table without that interaction because the p-value was 0.491. The Part*Operator and Operator*Subcomponent interactions are significant sources of variability and are retained in the model.
· Note that in the %Contribution column in the Variance Components table the percent contribution from Part-To-Part (92.08) is larger than that of Total Gage R&R (7.92). This tells you that much of the variation is due to differences between parts. Additionally, the sub-component does not add much additional part-to-part variation, only 1.44 percent.
· Note that in the %Study Var column in the Gage Evaluation table the Total Gage R&R accounts for 28.15% of the study variation. While the Total Gage R&R %Contribution is acceptable, there is room for improvement. See Guidelines for measurement system acceptability.
· For these data, the number of distinct categories is 4. According to the AIAG, you need at least 5 distinct categories to have an adequate measuring system. See Number of distinct categories statement.
Graph Window Output
· The Components of Variation graph (located in the upper left corner) shows that the percent contribution from Part-To-Part is larger than that of Total Gage R&R, telling you that much of the variation is due to differences between parts.
· The non-level line in the By Part graph (located in upper right corner) shows that there are large differences between parts.
· The R Chart by Operator (located in middle of the left corner) shows that Operator B measures parts inconsistently.
· The By Operator graph (located in the middle of the right column) shows that the differences between operators are small compared to the differences between parts, but are significant (p-value = 0.038). Operator C appears to measure slightly lower than the others.
· The Xbar Chart by Operator (located in the lower left corner) shows that most of the points in the X and R chart are outside the control limits, indicating variation is mainly due to differences between parts.
· The Operator* Subcomponent graph is a visualization of the p-value for Operator* Subcomponent (0.001), indicating a significant interaction between Operator and Subcomponent. All operators, especially Operator B, tend to measure Parts with Subcomponent B higher than parts with Subcomponent A.