Chapter 12 Flashcards
What is the interaction effect in both everyday terms and arithmetic terms?
The effect of the independent variable on the dependent variable. The mathematical way to describe an interaction of two independent variables is to say that there is a difference in differences.
What is done in experiments with one variable?
In a study with one independent variable, researchers look for a simple difference, such as the difference between being drunk or sober or the difference between being on a cell phone or not.
What is done in experiments with two variables?
When testing more than one variable, researchers are
testing for interactions, asking whether the effect of
one independent variable depends on the level of the
other one. An interaction is a “difference in differences.”
What are factorial designs?
Factorial designs cross two or more independent variables, creating conditions (cells) that represent every possible combination of the levels of each
independent variable.
Why are factorial designs beneficial?
Factorial designs can describe multiple influences on behavior; they enable researchers to test their theories and determine whether some manipulation affects one type of person more than another.
How does one analyse the data in factorial design?
Analyzing the data from a factorial design involves
looking for main effects for each independent variable by estimating the marginal means, then looking for interaction effects by checking for a difference in differences (in a line graph, interactions appear as
nonparallel lines).
How important are interaction effects?
When there is an interaction effect, it is more important than any other main effects.
What can factors be like in experiments?
- Independent-groups
- With-in-groups variables
- Manipulated (in-
dependent) variables - Measured, participant variables.
What needs to be considered in factorial designs with three or more independent variables?
When a factorial design has three or more independent variables, the number of interactions increases to include all possible combinations of the independent variables. In a design with three independent variables, the
three-way interaction tests whether two-way interactions are the same at the levels of the third independent variable.
How do you determine factorial designs when reading?
In empirical journal articles, the type of design is given in the Method section. In popular media stories, factorial designs may be indicated by language such as “it depends” and “only
when,” or descriptions of both participant variables and independent variables.
