Threats
Levels of the dependent variable change naturally over time
What are Maturation Threats?
Covariance of cause and effect, temporal precedence, and internal validity
When groups are not equivalent at assignment, nonequivalence may be the cause of group differences at posttest
What are Selection Effects?
Two or more IV, one DV, control all other variables
What are the requirements of a Factorial Experiment?
Significant p-values for independent variables
What are Main Effects in Covariance of Cause and Effect?
A major event occurred alongside the manipulation of the independent variable
What are History Threats?
One independent variable, one dependent variable (per test), and everything else is controlled
What is a Simple Experiment?
Experiencing one level of the independent variable might influence effects of other levels of the independent variable
What are Carryover Effects?
The effect of one independent variable across all levels of the other independent variable
What are Main Effects?
We have to assign people to groups before we measure the dependent variable
What is Temporal Precendence?
Must have pretest/posttest design for this threat
What are the requirements for Regression threats?
What is an Independent-Groups?
Participants may improve (or get worse) at a task over time, regardless of independent variable
A second independent variable that can change the effect of the first independent variable
What are Moderators?
We must address selection and order effects for ALL independent variables
How do we establish Internal Validity?
What are Demand Characteristics?
Participants complete the dependent measure twice, once before and once after exposure to the independent variable
What is Pretest/Posttest Design?
Too large a percentage of participants achieve the higher score on a test
What are Ceiling Effects?
Independent Variable A has a larger effect on the Dependent Variable at one level of Independent Variable B compared to the other levels
Type of test we use whenever we have within-groups designs
What is a repeated measures ANOVA?
Participants adjust their outcome because they believe they are receiving a treatment
What is a Placebo Effect?
Participants complete the dependent measure once, after exposure to the independent variable
What is Posttest-Only design?
Practice effects and Carryover effects
What are the Order effects?
Independent Variable A has reversed effect on the Dependent Variable at one level of Independent Variable B compared to the other level
What are Crossover Interactions?
Measuring how each combination of levels differ from each other combination of levels
What is a Post-hoc t-test?