Chapter 8 - Experimental Design Flashcards
Between-Subjects Design (also Independent Groups Design)
The between-subjects research design is an experiment in which different subjects are assigned to each group. It is also called an independent groups design.
Attrition (also Mortality)
Attrition refers to the loss of subjects who decide to leave an experiment.
Carryover Effect
The carry-over effect is a problem that may occur in repeated measures designs if the effects of one treatment are still present when the next treatment is given.
Confounding Variable
A confounding variable is a variable that is not controlled in a research investigation. In an experiment, the experimental groups differ on both the independent variable and the confounding variable.
Counterbalancing
Counterbalancing is a method of controlling for order effects in a repeated measures design by either including all orders of treatment presentation or randomly determining the order for each subject.
Fatigue Effect
The fatigue effect is when someone scores poorly or doesn’t do as well as they possibly could have on the second part of a test or measurement because the first part tired them out.
Independent Groups Design (Between-Subjects Design)
The independent groups design is an experiment design in which different subjects are assigned to each group. It is also called a between-subjects design.
Internal Validity
Internal validity refers to the certainty with which results of an experiment can be attributed to the manipulation of the independent variable rather than to some other, confounding variable.
Latin Square
A Latin square is a technique to control for order effects without having all possible orders.
Learning Effect (also Practice Effect)
The learning, or practice effect, is an improvement in participant performance with repeated testing.
Matched Pairs Design
The matched pairs design is a method of assigning subjects to groups in which pairs of subjects are first matched on some characteristic and then individually assigned randomly to groups.
Mortality (also Attrition)
Mortality refers to the loss of subjects who decide to leave an experiment. Mortality is a threat to internal validity when the mortality rate is related to the nature of the experimental manipulation.
Order Effect
The order effect, in a repeated measures design, is the effect that the order of introducing treatment has on the dependent variable.
Posttest-only Design
A posttest-only design is a true experimental design in which the dependent variable (posttest) is measured only once, after manipulation of the independent variable.
Practice Effect (also Learning Effect)
The practice effect is an improvement in participant performance with repeated testing.
Pretest-Posttest Design
The pretest-posttest design is a true experimental design in which the dependent variable is measured both before (pretest) and after (posttest) manipulation of the independent variable.
Random Assignment
Random assignment is the use of a random “chance” procedure (such as a random number generator or coin toss) to determine the condition in which an individual will participate.
Repeated Measures Design (also Within-Subjects Design)
The repeated measures design is an experimental design in which the same subjects are assigned to each group. This is also called a within-subjects design.
Selection Differences
Selection differences refer to differences in the type of subjects who make up each group in an experimental design; this situation occurs when participants elect which group they are to be assigned to.
Within-Subjects Design (also Repeated Measures Design)
A within-subjects experimental design is an experiment in which the same subjects are assigned to each group. It is also called a repeated measures design.
