Example of a 3D surface plot
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Your company manufactures frozen foods and you need to determine the optimal time and temperature for reheating a new frozen entree. You reheat samples at a number of different times and temperatures, then have trained judges rate each for overall quality on a scale of 0 (not enjoyable) - 10 (most enjoyable). Create a 3D surface plot to examine the results.

Create a 3D surface plot

1    Open the worksheet REHEAT.MTW.

2    Choose Graph > 3D Surface Plot.

3    Choose Surface, then click OK.

4    In Z variable, enter Quality. In Y variable, enter Time. In X variable, enter Temp.

5    Click Scale, then click the Gridlines tab.

6    Under Show gridlines for, check Z major ticks, Y major ticks, and X major ticks.

7    Click OK in each dialog box.

Interpreting the results

Reheating at the shorter time intervals results in under-cooked product and low quality scores. However, reheating at the longest intervals combined with the highest temperatures also results in low scores because the food becomes over-cooked.

Adding the gridlines helps you visualize the peaks and valleys of the surface and determine the corresponding x- and y-values.

 

Rotating the graph to view the surface from different angles can help you visualize the peaks and valleys of the surface.

Rotate the plot

1    If the 3D Graph Tools toolbar is not visible, choose Tools > Toolbars > 3D Graph Tools.

2    Click and hold the button until the graph has rotated approximately 45° about the z-axis.

Interpreting the results

Rotating the graph helps accentuate the ridge of high z-values centered at about Time 35 and Temp 425.

Changing the graph lighting can help reveal different features of the data surface.

Rotate the lights

1    Click and hold the button on the 3D Graph Tools toolbar until the lights have rotated approximately 60° about the y-axis.

Interpreting the results

Rotating the lights to illuminate the low Time-Temp face of the ridge helps define its features. There appears to be a peak at about Time = 35 and Temp = 400.

Additional examples that help visualize these data include:

·    Scatterplot with connect line

·    Scatterplot with connect lines and groups

·    3D scatterplot

·    3D wireframe plot

·    Contour plot