Factorial Designs Flashcards
What are factorial designs?
Designs which include multiple independent variables.
What is the name of an experimental design with one IV? Two IVs? Three IVs?
One-way design.
Two-way design.
Three-way design.
What is a 2x3 experimental design?
When the first IV has two levels and a second IV has three levels.
E.g., coffee X time of day
- Factor coffee has two levels: cup of coffee or cup of water.
- Factor time of day has three levels: morning, afternoon, and evening.
What is a 3x2x4 experimental design?
When there are multiple IVs with multiple levels each.
E.g., coffee X time of day X exam duration
Factor coffee has three levels: 1 cup, 2 cups, 3 cups
Factor time of day has two levels: morning or evening
Factor exam duration has 4 levels: 30min, 60min, 90min, 120min
What is a mixed design?
If at least one IV is between-groups and at least one IV is within-groups.
What is the effect of a single variable known as?
Main effect
What is the effect of two variables considered together known as?
Interaction effect
For two-way between-groups design, an omnibus F-ratio is calculated for what 3 things?
- Main effect of the first variable
- Main effect of the second variable
- Interaction between the first and second variables
What are the 4 steps of analysing a two-way between-groups design?
- State the null hypotheses (𝐻_0)
- Partition the variability
- Calculate the mean squares
- Calculate the F-ratios
How many null hypotheses are there for a two-way between-groups design?
3.
What refers to the residual error? What is this?
S/AB. This is what’s left over when we’ve accounted for A.
What is the F-ratio for the main effect of A?
MSA / residual error.
What is the F-ratio for the main effect of B?
MSB / residual error.
What is the F-ratio for the main effect?
MSAB / residual error.
