Experimental Study Designs
Uses random assignment to assign participants to experimental or control groups with a measure before and after the treatment/intervention.
What is a pre-test/post-test design?
This controls for participants' expectations about the effect of the treatment/intervention.
What is a placebo or a placebo group?
"(# levels of IV1) x (# levels of IV2) x (# levels of IV 3)" is this.
What is the general format of factorial designs?
To factorial design as well as data can be shown in this non-graph visual format.
What is a table/chart?
Self-report, behavioral, and physiological are all types of this variable.
What is the dependent variable?
A disadvantage to this study design is that you cannot tell if groups are the same or different at the start of the study.
What is the post-test only design?
Though adding time to a study, this approach reveals issues with participant instructions, wording of questions, plausibility of the setting of the experiment, among other things; allowing for changes to be made prior to the larger study.
What is a pilot study?
The number of conditions in a 2x2x2 factorial design.
What is 8?
In a line graph of a factorial design, a main effect for an independent variable can be visually identified in either of these two ways.
What is one line being higher than the other and one side of the graph being higher than the other?
The types of variable in an IV x PV factorial design.
What is a manipulated independent variable and a participant variable?
Allows for the testing of additional independent variables and/or additional levels of independent variable(s).
What is factorial designs?
"Please rate how much you like what I gave you" - one of the questions from the class activity last week, is an example of this.
What is a manipulation check?
This checks to see how well you manipulated the IV. Was I actually providing you with something you like?
The effect each independent variable has on the dependent variable without considering the other IVs.
What is a main effect?
In a factorial design line graph, you look for this characteristic to identify a possible interaction.
What is that the lines that are NOT parallel?
Heart rate, BMI, MRI, EEG
What are examples of physiological measures of the dependent variable?
This study design controls for the potential effect of the pre-test on the post-test.
What is the Solomon four-group design?
Via random assignment, half of the participants are in a post-test only design and half are in a pre-test / post-test design, both receiving the same intervention. This will identify any impact of the pre-test on the post-test.
Placebo is a control treatment/control group used in experimental studies. The use of a placebo and an experimental treatment in a study when participants do not know which they are receiving is this.
What is blinding? or What is a single-blind study?
The effect of one IV observed at each separate level of the other IV on the dependent variable.
What is a simple main effect?
The graph that represents two main effects and no interaction. (see last slide of week 10 power point presentation)
What is Graph B?
Reasons to include more than one outcome measure in a study. (at least 2 of the 3)
What are "variables can usually be measured in more than one way," "greater confidence in the relationship if the IV has the same effect on multiple measures of the DV," and "interest in assessing the effect of the IV on multiple variables/behaviors."
This study design is used when sample size is small and repeated measures is not possible and your study is doubly impacted if one participant drops out.
What is a matched pairs design?
Automating procedures, running all conditions at the same time, training and practicing, and double or triple blinding are examples of this.
What are ways to address experimenter bias? or What are experimenter controls?
Two main effects, one interaction, and four simple main effects are the possible outcomes for what type of factorial design.
What is a 2x2 factorial design?
A factorial design table with data averages can be used to determine and describe these three relationships, even without graphing the data.
What are main effects, simple effects, and interactions?
It also allows you to easily identify the type of factorial design (e.g. 2x2 or 2x2x3, etc.)
In a matched pairs design, the matching variable must be strongly related to this.
What is the dependent variable?
Matching on this variable ensures groups are equivalent on the matching variable prior to the IV manipulation and controls for a factor you know to be an important risk factor or variable, thereby controlling for this potential confounder when repeated measures isn't possible.