Mixture Design Tutorials - Statease.info

Response Prediction
Design-Expert allows you to generate predicted response(s) for any composition. To see
how this works, click on the Point Prediction node under optimization.
Point Prediction Results
You now see the predicted responses from this particular blend - the centroid. Be sure to
look at the 95% prediction interval (“PI low” to “PI high”). This tells you what to
expect for an individual confirmation test. You might be surprised at how much
variability could affect the outcome.
Although there’s no reason to do so now, you can print the results by using the File,
Print command.
The Factors Tool will open along with the point prediction window. Move the
floating tool as needed by clicking on the top border and dragging it. You can drag the
handy sliders on the component gauges to look at other blends. Note that in a mixture
you can only vary two of the three components independently. Can you find a
combination that produces viscosity of 43? (Hint: push Urea up a bit.) Don’t try too
hard, because in the next section of this tutorial you will make use of Design-Expert’s
optimization features to accomplish this objective.
Click on the Sheet button to get a convenient entry form for specific component values.
For example, to get the centroid back, enter the values shown below.
Factors Tool – Gauges versus Sheet View (with value being entered for Urea)
Click back to the Gauges view before proceeding.
7-22 • Mixture Design Tutorials Design-Expert 6 User’s Guide