Specify random or nested factors for Fit General Linear Model

Stat > ANOVA > General Linear Model > Fit General Linear Model > Random/Nest

Specify whether each factor is nested within another factor and whether each factor is a fixed or random factor.

Nesting

Factor/Covariate: Displays all the factors and covariates that are in the model. This column does not take any input.
Nested in specified factors: If a factor is nested in one or more factors, enter those factors. For multiple levels of nesting, enter only the factors that a factor is directly nested in. For example, assume that C is nested in B and B is nested in A. For C, enter only B.

Factor type

Factor: Displays all the factors that are in the model. Covariates are not listed here. This column does not take any input.
Type: Select Fixed or Random from the drop-down list. If your model contains random factors, you must specify a hierarchical model in the Model sub-dialog box.
Note
For a model with random factors, you usually use Fit Mixed Effects Model so that you can use the Restricted Maximum Likelihood estimation method (REML).

Note

If your model includes nested factors or random factors, or if it uses binary coding, there are restrictions on the procedures that you can perform. For more information, go to Restrictions for General Linear Models.