Design Points (Vertices & Centroids) for Constrained Surfaces and Mixtures
Standard Designs for Mixture Experiments
Select Designs for constrained surfaces and mixtures from the Advanced tab of the Design and Analysis of Experiments Startup Panel to display the Design Points (Vertices & Centroids) for Constrained Surfaces and Mixtures dialog. This dialog contains two tabs: Quick and Options.
The Experimental Design module contains an implementation of an algorithm suggested by Piepel (1988) and Snee (1985) for finding vertex and centroid points for regions or mixtures subject to linear constraints. The Introductory Overview discusses the logic of this algorithm. In short, each linear constraint:
A1x1 + A2x2 + ... + Aqxq + A0 ³ 0
(where the Ai's are weights, and the xi's denote the factor values) defines a line (or plane) through the experimental region; you can specify a practically unlimited number of such constraints, which Statistica processes one by one, to determine the vertex points resulting from the intersection of the constraint lines (planes). After all constraints have been processed, Statistica then computes the respective centroids for each side of the (convex) hyperpolyhedron.
OK. Click the OK button to generate the design and display the appropriate results dialog (either the Constrained Mixture Design Results dialog or the Constrained Surface Design Results dialog).
- Cancel
- Click the Cancel button to close the dialog and return to the Startup Panel.
- Options
- Click the Options button to display the Options menu.