Advanced Design of Experiments: 2-Level Factorial/Screening Designs Dialog

SigmaXL > Design of Experiments > Advanced Design of Experiments: 2-Level Factorial/Screening > 2-Level Factorial/Screening Designs

• Number of Continuous Factors – select 0 to 19 continuous factors. Modify Factor Names and Level Settings (Continuous) as needed. Name is text, Low and High settings are numeric.


• Number of Categorical Factors – select 0 to 19 categorical factors. Modify Factor Names and Level Settings (Categorical) as needed. Name is text, Low and High settings are text. Categorical factors are 2 level only and are coded as Low = -1, High = +1. They are treated the same as continuous for regression analysis except quadratic terms cannot be estimated and prediction/optimization restrict the inputs to the specified categorical levels. If center points are added, all categorical combinations are included for each center point, hence they are pseudo center points. If there are no continuous factors, Number of Center Points per Block is greyed out.


• Tip: If more than two levels are required for categorical, use General Full Factorial, Response Surface Designs or Optimal Designs.


• The minimum number of continuous factors + categorical factors = 2. The maximum number = 19.


• Select Design – available options will depend on the total number of continuous + categorical factors.


• Number of Replicates – select 1 to 10. Design Power Information with power to detect an effect size of 0.5*StDev to 3.0*StDev will be updated with selection.


• Number of Blocks – available options will depend on design and number of replicates. Design Power Information will be updated with selection if Include Blocks in Model is checked.


• Number of Center Points per Block – select 0 to 30. Design Power Information will be updated with selection.  If there are categorical factors these are called pseudo center points.


• Design Power Information – Terms in Model – select from One Main Effect, All Main Effects or ME + 2-Way Interactions:


• Error degrees of freedom (df) = #Total Runs – #Specified Terms in Model – 1 (for constant).
• If Include Blocks in Model and/or Include Center Points in the Model are checked, Error df is adjusted.
• If Error df is 0, an error message is given.
• If the specified number of terms exceeds the maximum permitted, only the maximum will be used.
• For formula details, see the Appendix: 2-Level Factorial/Screening Design – Power Calculations.


• Design Power Information – Number of Terms Omitted from Model – enter value, default is 0:


• Use this option to include all terms in the model when there are 3-Way Interactions or higher
• Error df = #Total Runs – (#Design Runs - #Terms Omitted from Model) – 1.


• Design Power Information – Significance Level – enter alpha value, default is 0.05.


• Randomize Runs– check to randomize runs with Seed (Base) as either Clock or specified Value. The latter will randomize the runs but always in the same random order for the same seed value. If unchecked, runs are in given in standard order.


• Randomize Center Points – uncheck to make center points (approximately) equal spaced within a block. If checked Center Points are randomized. This option is not available if Randomize Runs are unchecked.


• Aliasing of Effects Report with Interactions to Order – enter value, default is 2.


• Number of Responses – specify number of responses and enter Response Name.