Two-Way ANOVA

Lecture 4

When would you use a Two-Way ANOVA?

• 2 IVs

  • each have 2 or more levels

  • levels are independent of each other

• 1 DV

• ex. effect of age and aerobic training on trained and untrained individual (this example has 4 groups)

What are the prerequisites for performing a Two-Way ANOVA?

• IVs need to be categorical

  • cannot be continuous

• DV is continuous

• normal distribution of the DV

  • minor distribution errors are ok bc ANOVA is considered “robust”

• homogeneity of variance

Define Main Effects.

effect of IV on DV

Define Interaction.

the 2 IVs can interact with each other and influence the DV

• the findings are sometimes very important

When should you use a Post-Hoc test after a Two-Way ANOVA?

when the results are significant

What tests could you perform if the Main Effects from a Two-Way ANOVA are significant?

• post-hoc within the effects

• post-hoc across the effects

• no need for Post-Hoc if IV only has 2 levels!

When could results be described as “a trend or tendency to be different?”

when p < 0.1

How does the significance of the Main Effects and/or the Interaction effect the discussion section of an analysis?

it should be noted how the IVs interacted with each other and the appropriate Post-Hoc tests should be performed and discussed