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A central composite design is the most commonly used response surface designed experiment. Central composite designs are a factorial or fractional factorial design with center points, augmented with a group of axial points (also called star points) that let you estimate curvature.   

Use Create Response Surface Design (Central Composite) to create a designed experiment for 2−10 factors to model curvature in your data and identify factor settings that optimize the response.   

Choose Stat > DOE > Response Surface > Create Response Surface Design. Under Type of Design, select Central composite. From Number of continuous factors, select 3. Click Designs. Select the second design (full design with 20 runs and 2 blocks) in the white box, and then click OK. Click Results.   

For a central composite design, the number of orthogonal blocks depends on the number of factors, the number of runs, and the design fraction you choose. A central composite design can always be separated into a factorial block and an axial point block.   

Summary of central composite designs. The table summarizes the designs generated by the central composite design commands. If the design has blocks, then the blocks are orthogonal.   

To view a design in standard order or random order, use Display Response Surface Design. To randomize or re-randomize a design, use Modify Design. For more information, go to Overview for Display Design and Modify Design.   

Enter how many times to perform each experimental run that is in the base design. Usually, you consider the available resources and the purpose of your design when you select the number of replicates. You can add replicates to your design later with Stat > DOE > Modify Design.   

Complete the following steps to specify that you want to create a central composite design. You can click Display Available Designs to view characteristics of the central composite and Box-Behnken designs that Minitab creates.   

Create Response Surface Design (Central Composite): Use to create a factorial or fractional factorial design that includes center points, augmented with a group of axial points (also called star points) that let you estimate curvature.   

Learn more about Minitab. Stat > DOE > Response Surface > Create Response Surface Design > Factors. Complete the following steps to specify details about the factors in the design. Under Levels Define, choose if the factor setting represent Cube points or Axial points.