Minitab calculates the predicted responses using the global solution variable settings. The predicted responses are the responses that you can expect if the global solution variable settings are used.

For the predicted responses, the confidence interval (CI) is a range of values that is likely to contain the mean response for a selected combination of variable settings.

The prediction interval (PI) is the range that is likely to contain a single future response for a selected combination of variable settings.

The prediction interval is always wider than the corresponding confidence interval because of the added uncertainty involved in predicting a single response value versus the mean response.

For the tire manufacturing process, the global solution variable settings are temperature = 466.496, curing time = 37.3949, and density = 9.31821.

The predicted responses indicate that, according to the fitted models, tires produced using these factor settings will, on average, exhibit the following properties:

·    an elasticity of 100.00

·    a puncture resistance of 947.8

Both of these quality characteristics fall within the acceptable boundaries. The confidence intervals and prediction intervals indicate that the range of likely values for puncture resistance falls within the acceptable boundaries. However, the upper ends of the intervals for elasticity exceeds the maximum design parameter of 106.508. The results are too imprecise. The researchers should conduct additional experimentation and/or use a larger sample size to improve the precision of the predicted response for elasticity.