Example of Create Plackett-Burman Design

A research team wants to screen 9 factors down to a smaller set for further experimentation. The team decides to use a 12-run design with 3 center points. In this design, each main effect is partially aliased with more than one 2-way interaction.

  1. Choose Stat > DOE > Factorial > Create Factorial Design.
  2. Under Type of Design, select Plackett-Burman design.
  3. From Number of factors, select 9.
  4. Click Designs.
  5. In Number of runs, select 12.
  6. In Number of center points per replicate, enter 3. Click OK.
  7. Click Results. Select Summary table and design table.
  8. Click OK in each dialog box.

Interpret the results

In the first table, the total number of runs shows the number of runs in the Plackett-Burman design plus any center points. For this example, the team chose 12 points and added 3 center points, for a total of 15 runs.

The design table shows the experimental conditions or settings for each of the factors for the design points. For example, in the first run of the experiment, Factors A, B, C, E, F, and H are at the high setting. Factors D, G, and J are at the low setting.

Note

Minitab randomizes the design by default, so if you replicate this example your run order will not match the order in the example output.

Design Summary

Factors:9Replicates:1
Base runs:15Total runs:15
Base blocks:1Total blocks:1
Center points: 3

Design Table (randomized)

RunBlkABCDEFGHJ
11+++-++-+-
21+-+---+++
31--+++-++-
41+-++-+---
51-+---+++-
61000000000
71000000000
81000000000
91---------
101---+++-++
111-+++-++-+
121++-++-+--
131-++-+---+
141+---+++-+
151++-+---++