12.1 Learning Outcomes

After completing this lab, you should be able to

  • Conduct one-way and factorial ANOVAs in R Commander and SPSS
  • Interpret the output of one-way and factorial ANOVAs from R Commander and SPSS
  • Report the results of one-way and factorial ANOVAs in APA style

Before you begin, make sure you understand the following concepts from the lecture portion of the course

  • The goal of ANOVA, including what types of research questions it can be used to test
  • The difference between one-way and factorial ANOVA

This lab will also draw on the following skills learned in earlier labs. You can review previous labs at any time.

You can download the dataset we will be using in this lab here. The dataset contains simulated (i.e., not real) data from 240 patients seeking treatment from an addictions treatment centre. Each patient is seeking treatment for the use of one of three substances: cannabis, alcohol, or opioids. Patients are randomly assigned to receive in-patient treatment (treatment condition) or to remain on a waitlist for treatment (control condition). The dataset contains the following variables:

  • rid: Research ID
  • substance: Substance for which the participant is seeking treatment, with levels cannabis, alcohol, and opioids
  • condition: Experimental condition, with levels treatment and control
  • bam: Score on the Brief Addiction Monitor. Scores range from 0–66, with higher scores indicating greater levels of addiction
  • gender: Gender, with levels woman and man