A response trace plot (also called a component effects plot) shows how each component affects the response relative to a reference blend. If the design contains process or amount variables, they must be held at a fixed level.

The fondue data has three components and one process variable. Previous investigation has shown that the fondue tastes the best when it is served at 90°. Therefore, Temperature has been fixed at 90.0 (high level). For the fondue data, the reference blend is the center point.

The trace plot provides the following information about the component effects. Starting at the location corresponding to the reference blend:

As the proportion of Emmenthaler in the mixture:

·    Increases (and the other mixture components decrease), the flavor rating increases

·    Decreases (and the other mixture components increase), the flavor rating decreases

As the proportion of Gruyere in the mixture:

·    Increases (and the other mixture components decrease), the flavor rating increases rapidly

·    Decreases (and the other mixture components increase), the flavor rating decreases rapidly

As the proportion of white wine in the mixture:

·    Increases (and the other mixture components decrease), the flavor rating decreases

·    Decreases (and the other mixture components increase), the flavor rating increases

Based on these findings, you may want to increase the proportion of both Emmenthaler and Gruyere cheese, and decrease the proportion of wine in the fondue.