Interaction plots display the interaction between two factors. An interaction occurs when the effect of one factor is dependent upon a second factor. This plot is the graphical analog of the F-test for an interaction term in the ANOVA table.

Gage studies generally examine the part by operator interaction. However, Gage R&R Study (Expanded) allows you to graph other interactions. The Part*Operator graph shows the average measurements that are taken by each operator on each part in the study, arranged by part. Each line connects the averages for a single operator (or term that you specify).

Ideally:

·    the lines follow the same pattern

·    the part averages vary enough that differences between parts are clear

For the refraction data, the lines follow each other fairly well. This graph is a visualization of the ANOVA table p-value for Part*Operator (0.189). There are a few inconsistencies. For example, Operator 3 has a notably different measurement for part 19 than the other two operators.