Build Terms and Custom Terms
- Build terms
- Use this choice when you want to include non-nested terms of a certain type (such as main
effects) for all combinations of a selected set of factors and covariates.
- Select one or more factors or covariates or a combination of factors and covariates.
- Select a method for building the terms and
click Add.
- Interaction
- Creates the highest-level interaction term of all selected variables. This is the default.
- Main effects
- Creates a main-effects term for each variable selected.
- All 2-way
- Creates all possible two-way interactions of the selected variables.
- All 3-way
- Creates all possible three-way interactions of the selected variables.
- All 4-way
- Creates all possible four-way interactions of the selected variables.
- All 5-way
- Creates all possible five-way interactions of the selected variables.
- Repeat the process until you have all of the terms that you want in the model.
- Build custom terms
- Use this choice when you want to include nested terms or when you want to explicitly build any
term variable by variable. Building a nested term involves the following steps:
- Select a factor or covariate that is nested within another factor and click the move button.
- Click Within.
- Select the factor within which the previous factor or covariate is nested and click the move button.
- Click Add.
- Optionally, you can include interaction effects by using By, or you can add multiple levels of nesting to the nested term.