User Guide

385
GLM Univariate
Analysis
GLM Profile P
lots
Figure 22-5
Univariate Profile Plots dialog box
Profile plots (interaction plots) are useful for comparing marginal means in your
model. A profile plot is a line plot in which each point indicates the estimated
margin
al mean of a dependent variable (adjusted for any covariates) at one level of a
factor. The levels of a second factor can be used to make separate lines. Each level in
a third factor can be used to create a separate plot. All fixed and random factors, if
any, ar
e available for plots. For multivariate analyses, profile plots are created for
each dependent variable. In a repeated measures analysis, both between-subjects
factors and within-subjects factors can be used in profile plots. GLM Multivariate
and GL
M Repeated Measures are available only if you have the Advanced Models
option installed.
A profile plot of one factor shows whether the estimated marginal means are
incre
asing or decreasing across levels. For two or more factors, parallel lines indicate
that there is no interaction between factors, which means that you can investigate the
levels of only one factor. Nonparallel lines indicate an interaction.