Repeated measures

Starting with Prism 8, three-way ANOVA can handle repeated measures. Three checkboxes let you specify which of the factors are, and are not, repeated measures. As you check and uncheck these options, look at the graphic on top of the screen which tries to show you the design you have selected.

Assume sphericity?

Choose whether to assume sphericity on the RM Analysis tab, along with the method used to analyze repeated measures. Learn about the RM Analysis tab.

Random or fixed factors?

Read an advanced stats book to learn about random and fixed factors. Prism doesn't let you specify which factor(s) is/are random and which is/are fixed. It uses this rule:

•The row and column factors are considered to be fixed factors. You care about those exact levels of the factor. If there are three separate treatments, you care about those treatments. If there are four separate concentrations, you care about those concentrations (and have not selected those concentrations at random from all possible concentrations).

•When you choose repeated measures ANOVA, the participant or animal or subject is considered to be a random factor. You don't care about these particular participants or animals or whatever. Instead, they are assumed to be randomly selected from a larger population that you care about.