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Options

This page is the control by control reference for the pages the Create Design builder shows for this design. What the design is and what it gives you is on Plackett-Burman Design. How each number is produced is on Math Details.

Choosing the design

The page is headed Select Plackett-Burman design and asks two things, Select number of factors: and Select number of runs:.

The available run counts are 12, 20, 24, 28, 32, 36, 40, 44 and 48, and only those larger than the number of factors you asked for are offered. A design with n runs holds up to n - 1 factors.

The n - 1 cap holds for every size, including the 40-run design, which takes at most 39 factors.

The factor list runs from 2 to 47, and the box accepts a typed value, so three refusals are reachable here: Number of factors must be an integer greater than 1 and less than 48., Number of runs must be an integer value. and, when the two do not fit together, Invalid number of runs for given number of factors.

Two sizes are built from stored tables rather than by cycling a seed column: the 28-run design, from three hard-coded blocks plus a final all-low row, and the 40-run design, from 39 stored columns. That affects how they are generated, not how many factors they hold.

Center points

Plackett-Burman designs get no center points. There is no center points page in the build sequence, and Modify Design > Add/Remove Center Points refuses afterwards with center points are not available for the Plackett-Burman design.

The page sequence

Select Plackett-Burman design > Enter Factor Names and Coding > Define outputs (responses) > Enter number of replicates and number of blocks.

See Also