The optimization plot shows how the variables affect the predicted responses and allows you to modify the variable settings interactively.

·    Each column of the graph corresponds to a variable.

·    The top row of the graph corresponds to the composite desirability, if shown. Each remaining row corresponds to a response variable.

·    Each cell of the graph shows how the corresponding response variable or composite desirability changes as a function of one of the variables, while all other variables remain fixed.

·    The numbers displayed at the top of a column show the current variable settings (in red) and the high and low variable settings in the data.

·    The Predict link in the top left of the graph calculates the prediction for the current variable settings.

·    At the left of each response row, Minitab shows the goal for the response, the predicted response, y, at the current variable settings, and the individual desirability score.

·    The composite desirability, D, is displayed in the top row and the upper left corner of the graph.

·    The label above the composite desirability refers to the current setting and changes if you move the variable settings interactively. When the optimization plot is created, the label is Optimal. If you change the settings, the label changes to New. If you find a new optimal setting, the label changes to Optimal. If you save the current setting, the label changes to a number to indicate the position in the list of saved settings.

·    The vertical red lines on the graph represent the current settings.

·    The horizontal blue lines represent the current response values.

·    The gray regions indicate where the corresponding response has zero desirability.

For the resin defect data, the global solution is unrealistic because the Hours Since Cleanse cannot stay 0. Also, employees prefer to use the large screw because the large screw moves the resin pellets faster. So the employees interactively change the optimization plot to show settings with a lower composite desirability than the desirability of the global solution.

Current settings are temperature = 135, hours since cleanse = 8, and the size of the screw is large. At these settings, the predicted number of clump defects is 15.8290 and the predicted number of discoloration defects is 71.9746. The composite desirability of 0.0527 is lower than the desirability of the global solution because the predictions are much closer to the upper limits for numbers of defects. Although these predictions are below the limits, the employees click Predict in the plot so that they can compare the confidence intervals to the limits too.