Example of Simplex Design Plot
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In the Example of a simplex centroid design, you created a design to study how the proportions of three ingredients in an herbal blend household deodorizer affect the acceptance of the product based on scent. The three components are neroli oil, rose oil, and tangerine oil. To help you visualize the design space, you want to display a simplex design plot.

1    Open the worksheet DEODORIZ.MTW.

2    Choose Stat > DOE > Mixture > Simplex Design Plot. Click OK.

Graph window output

Interpreting the results

The simplex design plot shows that there are ten points in the design space. The points are as follows:

·    Three pure mixtures, one for each component (Neroli, Rose, and Tangerine). These points are found at the vertices of the triangle.

·    Three binary blends, one for each possible two-component blend (Neroli-Rose, Rose-Tangerine, and Tangerine-Neroli). These design points are found at the midpoint of each edge of the triangle.

·    Three complete blends. All three components are included in these blends, but not in equal proportions.

·    One center point (or centroid). Equal proportions of all three components are included in this blend.