Minitab displays the design parameters for each response in the Session window. You should check these results and verify that the displayed design parameters are correct.

Your choices of goal, lower, target, upper, and weight define the desirability function for each individual response. The importance (Import) parameters determine how the desirability functions are combined into a single composite desirability.

Response optimizer does not use the data in the worksheet. Instead, Minitab estimates the optimal variable values based on stored models. You must fit a model before you can use the response optimizer. If you want to optimize multiple responses, you must fit a model for each response separately. The optimal values are accurate only if all models represent the true relationships.

In the tire experiment, the response variables are elasticity and puncture resistance. The design parameters are as follows:

·    The goal for Elasticity is to obtain a value at or near the Target value of 100. Elasticity values less than 87.385 or greater than 106.508 are unacceptable.

·    The goal for Puncture Resistance is to Maximize it. A value of 924.882 or more is considered excellent, while values below 863.988 are unacceptable.

Notice the unequal importance values for the responses. The purpose of this study is to increase puncture resistance while maintaining elasticity in an acceptable range. The importance (Import) of elasticity is 1, whereas the importance of puncture resistance is 2. Therefore, puncture resistance will have greater influence on the composite desirability.