Week 9 - Experimental Designs/Quasi-Experimental Designs Flashcards
assigned to independent group
between-subjects design
subjects act as their own controls
within-subjects design
a way of describing an experimental design that is based on the number of factors
factorial design
name 3 types of experimental designs.
- btwn-subjects design
- within-subjects design
- factorial design
does not include either random assignment or a control group
quasi-experimental design
did the experimental treatment make the difference in this specific instance rather than extraneous variables
internal validity
name 7 threats to internal validity
- history
- maturation
- testing
- instrumentation
- selection bias
- experimental mortality
- interaction among factors
events occurring during the experiment that are not part of the treatment
history
biological or psychological processes within participants that may change due to the passing of time ex: aging, fatigue, hunger
maturation
the effects of one test upon subsequent administrations of the same test
testing
changes in testing instruments, raters, or interviewers including lack of agreement within and btwn observers
instrumentation
identification of comparison groups in other than a random manner
selection bias
loss of participants from comparison groups due to nonrandom reasons
experimental mortality
factors can operate together to influence experimental results
interaction among factors
- generalizability of results - to what populations, settings, or treatment variables can the results be generalized
- concerned with real-world applications
external validity
how is external validity controlled?
by selecting subjects, treatments, experimental situations, and tests to be representative of some larger population
what is the key to controlling most threats to external validity?
random selection
name 2 types of external validity.
- population validity
- ecological validity
refers to the extent to which the results can be generalized from the experimental sample to a defined population.
population validity
refers to the extent to which the results of an experiment can be generalized from the set of environmental conditions in the experiment to other environmental conditions
ecological validity
name 4 threats to external validity.
- interaction effects of testing
- selection bias
- reactive effects of experimental setting
- multiple-treatment interference
the fact that the pretest may make the participants more aware of or sensitive to the upcoming treatment
interaction effects of testing
when participants are selected in a manner so they are not representative of any particular population.
selection bias
the fact that treatments in constrained laboratory settings may not be effective in less constrained, real-world settings
reactive effects of experimental setting