Your response is Yield. Your factors are the following:
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Time: The range of interest is 500 to 560 seconds.
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Temperature: The range of interest is 350 to 750 degrees Kelvin.
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Catalyst: Three catalysts A, B, and C, must be tested.
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1.
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Select DOE > Custom Design.
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2.
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3.
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In the Factors outline, type 2 next to Add N Factors.
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4.
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Click Add Factor > Continuous.
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5.
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Click Add Factor > Categorical > 3 Level.
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Figure 4.46 Factor Settings
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Click Continue.
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Select Use Disallowed Combinations Filter in the Define Factor Constraints outline.
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2.
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3.
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Click Add.
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This disallows factor settings with Temperature values below 400.
5.
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Click the B block under Catalyst.
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Together with the constraint on Temperature, this disallows factor settings for which Catalyst is B and Temperature is below 400.
6.
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Click OR.
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7.
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Select Temperature and Catalyst from the Add Filter Factors list. (Your earlier selection may have been retained.)
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8.
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Click Add.
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This disallows factor settings with Temperature values above 650.
10.
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Click the C block under Catalyst.
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Together with the constraint on Temperature, this disallows factor settings for which Catalyst is C and Temperature is above 650.
Figure 4.47 Constraints Defined
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2.
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Click OK to dismiss the alert.
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Note: Setting the Random Seed in step 3 and Number of Starts in step 4 reproduces the exact results shown in this example. In constructing a design on your own, these steps are not necessary.
3.
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(Optional) From the Custom Design red triangle menu, select Set Random Seed, type 654321, and click OK.
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4.
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(Optional) From the Custom Design red triangle menu, select Number of Starts and set it to 1000. Click OK.
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5.
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Click Make Design.
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Figure 4.48 Design Satisfying Constraints
Recall that the design region consists of settings of Time between 500 and 560 and Temperature between 350 and 750. To obtain a geometric view of the design points within the design region, do the following:
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Click Make Table.
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2.
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Select Graph > Graph Builder.
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3.
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4.
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Deselect the Smoother icon. This is the second icon from the left above the template.
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5.
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Figure 4.49 Design Points for Three Levels of Catalyst
6.
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Double-click the Temperature axis.
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Next to Value, enter 350.
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Click Add.
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Next to Value, enter 750.
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Click Add.
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8.
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Click OK.
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9.
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Double-click the Time axis.
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Next to Value, enter 500.
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Click Add.
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Next to Value, enter 560.
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Click Add.
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11.
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Click OK.
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12.
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Click Done.
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Figure 4.51 Design Regions for Three Levels of Catalyst
Six of the settings for Catalyst A fall on the edges of the design region. All Temperature setting for Catalyst B are above the 400 degree constraint and all Temperature settings for Catalyst C are below the 650 degree constraint.