Use the ANOM interactions plot to test the hypothesis that there is no interaction between the factors in a two-way design at an a-level that you specify. The interactions plot shows the following:

·    Plotted points – the effects for each cell in the two-way design. The effects indicate the strength of the interaction.

·    Reference line – plotted at zero.

·    Lower and upper decision limits – used to test the hypothesis that each effect is equal to zero (that no interaction exists). Minitab looks for points located beyond the decision limits and marks them with a red symbol.

-    If one or more effects are beyond the decision limits, then you reject the hypothesis and conclude that there is statistical evidence of an interaction. Examining which cells are beyond the decision limits may help you to interpret the interaction.

-    If no effects are beyond the decision limits, then you cannot reject the hypothesis. There is no statistical evidence of an interaction.

For the driving values, none of the effects are beyond the decision limits, so no evidence of an interaction exists.