Overview

One-way ANOVA and Kruskal-Wallis

Last week you learnt how to use and interpret the general linear model when the x variable was categorical with two groups. You will now extend that to situations when there are more than two groups. This is often known as the one-way ANOVA (analysis of variance). You will also learn about the Kruskal- Wallis test which can be used when the assumptions of the general linear model are not met.

Learning objectives

The successful student will be able to:

  • explain the rationale behind ANOVA understand the meaning of the F values

  • select, appropriately, one-way ANOVA and Kruskal-Wallis

  • know what functions are used in R to run these tests and how to interpret them

  • evaluate whether the assumptions of lm() are met

  • scientifically report the results of these tests including appropriate figures

Instructions

  1. Prepare

    1. 📖 Read One-way ANOVA and Kruskal-Wallis

  2. Workshop

    1. 💻 One-way ANOVA
    2. 💻 Kruskal-Wallis

  3. Consolidate

    1. 💻 Appropriately test if fitness and acclimation effect the sodium content of sweat
    2. 💻 Appropriately test if insecticides vary in their effectiveness