Specifying custom tests for terms in MANOVA

In the Results sub-dialog box, you can specify model terms in Custom multivariate tests for the following terms and designate the error term in Error. Minitab performs four multivariate tests for those terms. This option is most useful when you have random factors. Model terms that are random or that are interactions with random terms may need a different error term than general MANOVA supplies. You can determine the appropriate error term by performing general linear model with one response variable. Then, you can use the expected mean square to determine which error term was used for each model term.

If you specify an error term, it must be a single term that is in the model. This error term is used for all the tests your perform. If you have different error terms for certain model terms, enter each term separately and use the general MANOVA dialog for each one. If you do not specify an error term, Minitab uses MSE.

With general MANOVA, there are two SSCP matrices associated with each term in the model, the sequential SSCP matrix and the adjusted SSCP matrix. These matrices are analogous to the sequential SS and adjusted SS in univariate general linear model. In fact, the univariate SS's are along the diagonal of the corresponding SSCP matrix. If you do not specify an error term in Error when you enter terms in Custom multivariate tests for the following terms, then the adjusted SSCP matrix is used for H and the SSCP matrix associated with MSE is used for E. If you do specify an error term, the sequential SSCP matrices associated with H and E are used. Using the sequential SSCP matrices guarantees that H and E are statistically independent.