10Inferential Analyses (ANOVAs)
Chapter Learning Objectives
- One‐way Command
- GLM Command
- UNIANOVA Command
When you are still interested in mean differences but find yourself dealing with more than two means at a time, you need to perform an analysis of variance (ANOVA) instead of a t‐test. There are three different ANOVAs that we're going to cover (although there are more types of ANOVA that could be specified).
You can think of ANOVAs as superordinate analyses to the two‐sample t‐tests. ANOVA can be applied to the two‐sample t‐test situation (except it reports an F instead of a t), but ANOVA has the flexibility to accommodate more than two means simultaneously. The one‐way ANOVA is used in an independent‐samples t‐test situation, the repeated‐measures ANOVA is used in a correlated samples t‐test situation, and the third ANOVA (factorial) doesn't really have a straight t‐test analogy – it is used when we have more than one predictor or independent variable (IV).
One‐Way ANOVA (One‐Way Command)
We'll use a prototypical drug and placebo example for the one‐way ANOVA; Figure 10.1 shows our syntax.
Running this syntax calls up the data file shown in Figure 10.2.
For the actual ANOVA analysis, we ...
Get IBM SPSS Essentials, 2nd Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
