Irfan Ahmed, PhD

Graphing Interactions in an ANOVA.   It is often useful to examine a plot of the means by condition when trying to interpret a significant interaction. To get plot of means by condition from SPSS • Perform a multifactor ANOVA as described above, but do not click the OK button to perform the analysis. • Click the Plots button. • Define all the plots you want to see. o To plot a main effect, move the factor to the Horizontal Axis box and click the Add button. o To plot a two-way interaction, move the first factor to the Horizontal Axis box, move the second factor to the Separate Lines box, and click the Add button. o To plot a three-way interaction, move the first factor to the Horizontal Axis box, move the second factor to the Separate Lines box, move the third factor to the Separate Plots box, and click the Add button. • Click the Continue button. • Click the OK button. In addition to the standard ANOVA output, the plots you requested will appear in a section titled Profile Plots .