Select Factor Values (When Creating Surface or Contour Plots).

Click the Surface plot or Contour plot button on the Prediction & profiling tab of an analysis results dialog box to display the Select factor values dialog box, provided there are more than two factors in the current experiment and/or there are blocks and a curvature check included in the current model.

Factor values
When there are more than two factors in the current experiment and/or there are blocks and a curvature check included in the current model, you can specify the values for those additional factors, for which to compute the surface or surface contours (i.e., for which to compute the fitted values) in the Factor values boxes. Remember that the block effects and curvature effect are computed from added (to the design) coded variables. The coding for those effects is described in the note on main effects and interactions for the respective results dialog (see below).
Common value
In the Common value box, specify a common value to use for all factors.
Apply
Click the Apply button to apply the value specified in the Common value box to all factors in the Factor values boxes.
OK
Click the OK button to accept the entries made in the Select factor values dialog box and return to the previous dialog box.
Cancel
Click the Cancel button to return to the previous dialog box. Any entries made in the Select factor values dialog box will be ignored.

See also the discussions of Main Effects and Interactions for Central Composite Experiments, Experiments with Three-Level Factors, Experiments with Two- and Three-Level Factors, Experiments with Two-Level Factors, and Screening Plackett-Burman) Experiments.