To determine the best factor settings for maximizing gas mileage while minimizing variability, we must return to Figure 8.12, 8.13, and 8.14. Base on Figure 8.12, set factor A at (1). Figure 8.13 indicates that factors B and D should be set at (1). Figure 8.14 indicates that factors C should be set at (-1) to minimizing variability. Thus, the final decision on setting the factors is as follows: