Topic 2 MIV Flashcards
Explain multiple independent variables
Allow us to understand how variables interact
Can observe how the relationship between one IV and DV can change as levels of other IV’s change
e.g time to fall asleep (DV), loud music vs lights on vs lights off (IV’s)
When is a study design considered ‘fully crossed’?
When there are a number of IV’s in the design and we collect data in all combinations of all levels of the IV’s
What are factors?
All IV’s all combined equally across all conditions
Describe factorial design
Each level of 1 factor is combined with every level of other variables
How is ‘2 x 2 factorial design’ determined?
In the example there are 2 independent variables and each IV has 2 levels
Describe a within-subjects design
- All IV’s are within-subject IV’s
- Each participant receives each of the possible conditions created by combining levels of the IV
Describe a Mixed design
- One IV is within-subjects
- One IV is between-subjects
- Each participant receives each level of the within-subjects IV and one level of the between-subjects IV
What are the two types of factorial effects?
- Main effects
2. Interaction effects
What are main effects?
The effects of one IV on the DV, ignoring other IV’s in the study
-There is a main effect for each IV
Describe interaction effects
Effects of one IV on the DV, taking into account other IV’s
-There’s an interaction for every combination of IV’s
-Looks at the relationship between one factor and DV, see how it changes as level of other factors change
Which effect should be interpreted first?
Interactions before main effect
What can diverging plotted lines tell you about an interaction?
That there is an interaction
What can intersecting plotted lines tell you about an interaction?
There is an interaction
What can parallel plotted lines tell you about an interaction?
There is no interaction, main effects may or may not be present
How many sources of variability would there be in a 2-factor experiemtn?
3
- > 2 main effects (one for each IV)
- > 1 interaction effect
