Design of a Central Composite (Response Surface) Experiment

Click the OK button in the Design & Analysis of Central Composite (Response Surface) Experiments dialog box to display the Design of a Central Composite (Response Surface) Experiment dialog box (if you have chosen to design an experiment via the Design experiment tab). This dialog box contains five tabs: Quick, Display design, Add to design, Design characteristic, and Generators & aliases. Use the options on these tabs to view the different aspects of the desired design. The Summary box (described below) is available regardless of which tab you have selected.

Summary box
The Summary box at the top of the dialog box displays the characteristics of the basic design (see Introductory Overview). Note that, when the design is blocked, the total number of runs in the standard design is broken down into 1) the number of cube points (nc), 2) the number of star points (ns), 3) the number of center points in the cube portion of the design (nc0), and 4) the number of center points in the star portion of the design (ns0). If the design is not blocked, nc0 and ns0 are not reported separately, but only one value n0 for the total number of center points is shown in the Summary box. The axial distance of the star points is indicated in the Summary box as Alpha for rotatability and Alpha for orthogonality. The concepts of rotatability and orthogonality are discussed in the Introductory Overview. The values listed in the Summary box are computed as described on the Design characteristic tab (see Box and Draper, 1987):
Note: the information in the Summary box is not updated (e.g., when you add center points), but always refers to the standard design. However, if you add center points to the design, and then click the Summary: Display design button (see below), the Alpha value will be recomputed before the design is displayed in the spreadsheet (depending on the choice of options on the Design characteristic tab). Also, the choice of axial distance and additional center points will be reflected in the Correlation matrix (main effects and interactions) on the Generators & aliases tab.
Copy button Click the Copy button to copy either the selected text (if text has been selected) in the Summary box or all of the text (if no text has been selected) to the Clipboard. Note that the copied text retains formatting information (such as font, color, etc.).
Contract/Expand button Click the Contract/Expand button to contract or expand the Summary box. When contracted, you can see only one line of the Summary box text and can scroll through the text using the scroll bar. Note that when contracted the text is scrolled so that the first non-blank line is at the top. When expanded (the default setting), the entire Summary box is displayed.
Summary
Click the Summary button to produce a spreadsheet specifying the settings for each experimental run. The way in which the design is displayed is affected by the respective settings of the options on the Display design tab. To save the design, select the spreadsheet and use the Save or Save As options via the File menu. Note that if you request to display text labels in your spreadsheet by selecting the Text labels option button in the Show (in Spreadsheet) group box on the Display Design tab, and then save it as a data file, Statistica will save the text labels along with the "underlying" factor minima and maxima. To use this spreadsheet in further analyses, you must specify it as an input spreadsheet. For more information, see the Input Spreadsheet Overview.
Cancel
Click the Cancel button to return to the Design & Analysis of Central Composite (Response Surface) Experiments dialog box.
Summary Box
Click the Summary Box button to send the information in the Summary box (see above) to a report. Note that if you don't have a Send to report option selected in the Output Manager, you will be prompted to select that option here. To send the results to a printer, see printing a report.
Options
Click the Options button to display the Options menu.