For any Fixed Factor, you can get marginal means (means adjusted for by other variables in the model) by clicking options. So if you have 5 fixed factors and don’t want to test 5-way interactions that you’ll never be able to interpret, you’ll need to create a custom model by clicking Model and removing some of the interactions.ģ. SPSS does that for you by default.Ģ.The default is for SPSS to create interactions among all fixed factors. You don’t have to create dummy variables for a regression or ANCOVA. There are a few things you should know about putting a categorical variable into Fixed Factors.ġ. SPSS will think those values are real numbers, and will fit a regression line. What you don’t want to do though, is to put a variable coded 1, 2, 3, 4, 5, 6 for the 6 categories into Covariates. Now, you can put a categorical variable into Covariates, as long as it’s coded properly–dummy or effect coding are common.
If it’s categorical, it goes in Fixed Factors. It does not matter if the variable is something you manipulated or something you are controlling for.
Put in your continuous dependent variable.įixed Factors are categorical independent variables. The dependent variable I hope is pretty straightforward. The down side of this flexibility is it is often confusing what to put where and what it all means. You can use it to analyze regressions, ANOVAs, ANCOVAs with all sorts of interactions, dummy coding, etc. The beauty of the Univariate GLM procedure in SPSS is that it is so flexible.
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