Two and Three-Way ANOVA Flashcards
When is an ANOVA used?
When there are more than 2 independent groups
What types of data does an ANOVA use?
Interval or Ratio (Parametric)
How many independent and how many dependent variables are found in a two-way ANOVA?
two independent variables and one dependent
What is an example of a two-way ANOVA?
Gender (there are two independent variables)
What are the two types of effects associated with two-way ANOVAs?
Main Effect and Interaction Effect
What is the main effect?
The effect of an independent variable on a dependent variable
*Essentially the overall effect of a factor (the interaction between factors is ignored)
What is the interaction effect?
The differing effect of one independent variable on the dependent variable, depending on the particular level of another independent variable
Describe how interaction effects work?
The various levels of the independent variables interact and affect the dependent variable differently than each by itself
For Example: There may be no effect when subjects receive independent variables separately, but when the independent variables are presented at the same time there is an effect (called the interaction effect)
What is the null hypothesis for an interaction effect?
States that there is no significant difference between the independent variables and all of their levels
H₀: uA1B1 = uA1B2 = uA2B1 = uA2B2 = uA3B1 = uA3B2
*You can see there are 2 levels for the 3 independent variables
In a summary table for a 2-way ANOVA (effect of stretch and knee position on ankle ROM example) what are the effects?
Main Effects: Stretch and Position
Interaction Effect: Stretch x Position
How many independent and how many dependent variables are found in a 3-way ANOVA?
three independent variables and one dependent
What is an example of a three-way ANOVA?
Ethnicity
In a 3-way ANOVA if the first independent variable has 3 levels, the second independent variable has 2 levels, and the third independent variable has 4 levels how is this design classified?
3 x 2 x 4 Factorial Design
Describe a Repeated Measures ANOVA design
Use the same subjects for numerous sets of data
What is an example of a repeated measures ANOVA?
SNEX (SNEX₀ SNEX₁ SNEX₂)
