GLM Syntax - Example 11: Cross-over design

This example illustrates the specification for a two-period crossover (change-over) design, for the estimation of carry-over effects. You can run this example with the example data file Grizzle.sta. The data set was originally described by Grizzle (1965), and the analysis of this crossover design is also discussed in Milliken and Johnson (1992, Section 32.2). Note that some effects require custom error terms (for these types of designs); you can choose those error terms via the Test option on the Results dialog.

GLM;

{ Dependent variable: }

   DEPENDENT = DV;

{ Specification of grouping variables (factors); note that

   no codes (values) are specified, so the program will by default

   take all grouping codes found in the data file. }

   GROUPS = SEQUENCE TREATMENT PERSON;

{ Refer to Milliken and Johnson (1992, Section 32.2) for a discussion of

  the specific terms (parameters) in the crossover design. Note that

  factor Person is specified as nested within Sequence. }

   DESIGN = SEQUENCE + PERSON(SEQUENCE) +

            TREATMENT + SEQUENCE*TREATMENT;

{ The overparameterized model is requested. }

   PARAM = OVERP;

{ Type I sums of squares decomposition is requested. }

   SSTYPE = 1;

For more examples, see GLM Syntax Examples.

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