Modify Design - Fold Design
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Stat > DOE > Modify Design > choose Fold design > Specify

Folding is a way to reduce confounding. Confounding occurs when you have a fractional factorial design and one or more effects cannot be estimated separately.

Dialog box items

Fold Design

Fold on all factors: Choose to fold the design on all factors.

Fold just on factor: Choose to fold the design on a single factor, then choose the factor from the list.