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Flashcards in Exam 3 Deck (45):

Attrition/ mortality

The loss of subjects who decide to leave an experiment


Carryover effect

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 variable that is not controlled in a research investigation. In an experiment, the experimental groups differ on both the IV and the confounding variable



A method of controlling for order effects in a repeated measures designed by either including all orders of treatment presentation or randomly determining the order for each subject


Fatigue effect

Deterioration in participant Performance with repeated testing


Internal Validity

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 technique to control for order effects without having all possible orders


Order effect

In a repeated measures design the effect that the order of introducing treatment have on the dependent variable


Practice Effect

Improvement in participant performance with repeated testing


Selection differences

Differences in the types of subjects who make up each group in an experimental design; this situation occurs when participants select which group they are to be assigned to


Solomon four group design

Experimental design in which the experimental and control groups are studied with and without a pretest



A person posing as a participants in an experiment who is actually part of the experiment


Demand characteristics

Cues that inform the subject how he or she is expected to behave


Electroencephalogram (EEG)

A measure of the electrical activity of the brain


Electromyogram (EMG)

A measure of the electrical activity of muscles including muscle tension


Expectancy effect(experimenter bias)

Any intentional or unintentional influence that the experimenter exerts on subjects to confirm the hypothesis under investigation


Filler items

Items included in a questionnaire measured to help disguise the true purpose of the measure


Functional MRI

Magnetic resonance Imaging uses a magnet to obtain scans of structures of the brain. Functional magnetic resonance imaging provides information on the amount of activity in different brain structures


Galvanic skin response

The electrical conductance of the skin which changes when sweating occurs


Factorial design

Design in which all levels of each independent variable are combined with all levels of the other independent variables. A factorial design allows investigation of the separate main effects and interactions of two or more independent variables


IV x PV design

A factorial design that includes both an experimental independent variable and a non-experimental participant variable


Main effect

The direct effect of an independent variable on a dependent variable


Mixed factorial design

A design that includes both independent groups and repeated measures


Simple effects

In a factorial design, the effect of one independent variable at a particular level of another independent variable



In a single case design, the subjects behavior during a control period before introduction of the experimental manipulation



A group of people born at about the same time and exposed to the same societal events; cohort effects are confounded with age in a cross-sectional study


Cross-sectional method

A developmental research method in which persons of different ages are studied at only one point in time; conceptually similar to an independent groups design


History effects

As a threat to the internal validity of an experiment, refers to any outside event that is not part of the manipulation that could be responsible for the results


Instrument decay

As a threat to internal validity, the possibility that a change in the characteristics of a measurement instruments, including human observers, is responsible for the results


Interrupted time series design

A design in which the effectiveness of a treatment is determined by examining a series of measurements made over an extended time. Both before and after the treatment is introduced. The treatment is not Introduced at a random point in time


Longitudinal method

Developmental research method in which the same persons are observed repeatedly as they grow older; conceptually some words are repeated measures design


Maturation affects

As a threat to internal validity, the possibility that any naturally occurring change within the individual is responsible for the results


Multiple baseline design

Observing behavior before and after a manipulation under multiple circumstances (across different individuals, different behaviors, or different settings)


Non equivalent control group design

A quasi Experimental design in which nonequivalent groups of subjects participate in the different experimental groups and there is no pretest


None equivalence control group pretest post test design

A quasi Experimental design in which nonequivalence groups are used but a pretest allows assessment of equivalency and pretest post test changes


One group posttest only design

A quasi Experimental design that has no control group and no pre-test comparison; a very poor design in terms of internal validity


One group pretest post test design

A quasi experimental Design in which the effect of an independent variable is inferred from the pretest post test difference in a single group


Propensity score matching

A method of pairing individuals for assignment to treatment and control condition based upon a combination of scores on participants variables


Quasi experimental design

A type of design that approximates the control features of true experiments to infer that a given treatment did have it intended effect


Regression toward the mean

Also called statistical regression; principle that extreme scores on a variable tend to be closer to the mean when a second measurement is made


Reversal design

Are you single case design in which the dream is introduced after a baseline Period and then withdrawn during a second baseline period. It may Be extended by adding a second introduction of the treatment. Sometimes called a withdrawal design


Selection differences

Differences in the types of subjects for make up each group in an experiment for design; this situation occurs when participants elect which group they are to be assigned to


Sequential method

A combination of the cross-sectional and longitudinal design to study developmental research questions


Single case experimental design

An experiment in which the effects of the independent variable is assessed using data from a single participant


Testing effects

A threat to internal validity in the witch taking a pretest changes behavior without any effect on the independent variable