CLASS Statement

Details of the OPTEX Procedure

CLASS class-variables ;: You use the CLASS statement to identify classification variables, which are factors that separate the observations into groups. For example, a completely randomized design has a single class-variable that identifies the groups of observations. A randomized complete block design has two class-variables; one identifies the blocks and one identifies the treatments.

Class-variables can be either numeric or character. The OPTEX procedure uses the formatted values of class-variables in forming model effects. Any variable in the model that is not listed in the CLASS statement is assumed to be continuous. Continuous variables must be numeric.

Note: If you specify a data set containing fixed covariate effects with a DESIGN= data set in the BLOCKS statement, then a CLASS or MODEL statement that follows the BLOCKS statement refers to the model for the fixed covariates. A CLASS or MODEL statement that defines the model for the candidate points (treatment model) should be specified before the BLOCKS statement.