# The idea of ANOVA

Reminders: A factor is a variable that can take one of several levels used to differentiate one group from another.

An experiment has a one-way, or completely randomized, design if several levels of one factor are being studied and the individuals are randomly assigned to its levels. (There is only one way to group the data.)

Example: Four levels of nematode quantity in seedling growth experiment.

But two seed species and four levels of nematodes would be a two-way design.

Analysis of variance (ANOVA) is the technique used to determine whether more than two population means are equal.

One-way ANOVA is used for completely randomized, one-way designs.