Mixture Design Tutorial (Part 2 – Optimization) - Statease.info

DX7-05B-Mix-P2.doc Rev. 4/12/06Point prediction set to solution #1Save the Data to a FileNow that you’ve invested all this time into setting up the optimization for this design, itwould be prudent to save your work. Click on the File menu item and select Save As.Save As selectionFinal CommentsYou can then specify the File name (we suggest tut-MIX-opt) to Save as type *.dx7”in the Data folder for Design-Expert (or wherever you want to Save in).We feel that numerical optimization provides powerful insights when combined withgraphical analysis. Numerical optimization becomes essential when you investigatemany components with many responses. However, computerized optimization will notwork very well in the absence of subject matter knowledge. For example, a naive usermay define impossible optimization criteria. The result will be zero desirabilityeverywhere! To avoid this, try setting broad acceptable ranges. Narrow them down asyou gain knowledge about how changing factor levels affect the responses. Often, youwill need to make more than one pass to find the “best” factor levels to satisfyconstraints on several responses simultaneously.With Design-Expert software, you can explore the impact of changing multiplecomponents on multiple responses, and find maximally desirable solutions quickly vianumerical optimization. (Don’t forget that you can set goals on the componentsthemselves – for example, in this case it might be wise to try maximizing the amount ofcheap water.) For your final report, finish up with a graphical overlay plot at theoptimum “slice.”Design-Expert 7 User’s Guide Mixture Design Tutorial – Part 2 • 21