Chapter 7 ANOVAs

t-tests, as we saw last week, were a simple way of comparing a continuous outcome between two groups or conditions (i.e. one categorical variable with two levels). However, it’s also common to compare across three or more groups when doing real research. To test this kind of hypothesis where we have three or more groups, we need to turn to a different method - the ANOVA. ANOVAs are useful when you have one categorical IV with 3+ levels, and one continuous DV.

The ANOVA is perhaps one of the most common statistical tests you will see in music psychology literature, in part because they generalise to a lot of research designs. In many respects, this week is fairly important in terms of knowing how to conduct an ANOVA and when. We’ll only be stepping through the basics this week, but there are some really important fundamentals to cover here.

It’s also common to analyse two independent variables against one dependent variable. These too can be done using ANOVAs. While we won’t go into this in this module, there will be an Extension Module that deals with this separately - check it out sometime around Week 10/11 if you’re interested.

By the end of this module you should be able to:

• Understand and describe the conceptual basis of an analysis of variance
• Describe how an ANOVA is calculated
• Conduct both one-way ANOVAs and one-way repeated ANOVAs, including their assumption tests
• Interpret the output of the ANOVAs and report their findings

Figure 7.1: xkcd: Third Way