Design of a Screening (Plackett-Burman) Experiment - Quick Tab

Generating the Design

Select the Quick tab of the Design of a Screening (Plackett-Burman) Experiment dialog to access the options described here.

Summary: Display design

Click the Summary: Display design button to display a spreadsheet specifying the settings for each experimental run. The design display is affected by the settings of the options on the Display design tab (see Denote factors, Order of runs, and Show (in Spreadsheet). 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 via the Display design tab, and then save it as a data file, then Statistica will save the text labels along with the "underlying" factor minima and maxima.

Note: Partial replications. If you want to replicate selected points from the design (e.g., so that you can later obtain an estimate of pure error; see Replicating the Design), first add rows to the design (use option Insert - Add Cases), and then copy and paste the respective runs into those new rows.

Order of runs

The choice of options in the Order of runs group box affects the order of runs displayed in the spreadsheet. For standard experiments, it is common practice to randomize the runs in order to avoid any systematic biases due to fluctuations in the production process across runs.

Standard order

Select the Standard order option button to display the design in standard order.

Random

Select the Random option button to randomize the order of runs. Note that if you choose to randomize the order of runs, the random number generator will use the seed specified on the Display design tab.

Change factor names, values, etc

Click the Change factor names, values, etc button to display the Summary for Variables (Factors) spreadsheet containing the current factor names, low and high values, corresponding text labels (for low and high values), and the nature of the factors (continuous or qualitative). Type in the desired text and numeric values, and then click the OK button; the values entered are then used in the spreadsheet displaying the design (option Summary: Display design, see above). See also, General User Entry Spreadsheet.