Main Effects Plotoverview how to example data see also
Main Effects PlotStat > ANOVA > Main Effects Plot
Use Main Effects Plot to plot data means when you have multiple factors. The points in the plot are the raw data means of the response variable at the various levels of each factor, with a reference line drawn at the grand mean of the response data. Use the main effects plot for comparing magnitudes of main effects.
This dialog generates a plot that uses data means. After you have fit a model, use the stored model to generate plots that use fitted means.
Data means are the raw response variable means for each factor level combination whereas fitted means use least squares to predict the mean response values of a balanced design. Therefore, the two types of means are identical for balanced designs but can be different for unbalanced designs. While you can use raw data with unbalanced designs to obtain a general idea of which main effects may be evident, it is generally good practice to use the fitted means to obtain more precise results.
Use Factorial Plots to generate main effects plots specifically for two-level factorial designs.
Responses: Enter the columns containing the response data.
Factors: Enter the columns containing the factor levels.