experiments Flashcards
controlled experiment
natural sciences in a lab: taking action and observing the consequences of that action
natural experiments
occur in the regular course of social events
dichotomous variable
variables with only 2 attributes.present or not present, men or women
pretesting
measurement of a dependent variable among subjects before they are exposed to a stimulus representing an independent variable
post testing
re-measurement of a dependent variable among subjects after they have been exposed to a stimulus representing an independent variable
double-blind experiment
neither the subjects nor the experimenters know which is the experimental group and which is the control group
randomization
technique for assigning experimental subjects to experimental and control groups randomly (assigning numbers and randomly picking)
matching
having a group with the same variables and splitting them up for experimental group and control group
one shot case study
single group of subject is measured on dependent variable following administration of some experimental stimulus
one group pre-test/post-test design
possible that some factor other than the independent variable might cause a change between the pre-test and post-test results
static-group comparison
shows something to one group but not to another and then measures the same variable in one group
Internal validity
possibility that the conclusions drawn from experimental results may not accurately reflect what went on in the experiment itself
-history (historical event)
-maturation (subjects grow older)
-testing (the experiment may let the people know what is being researched so it influence’s people’s behaviour)
-instrumentation (not the same survey given to experimental and control group)
-statistical regression (sometimes appropriate to conduct experiments on subjects who start out with extreme scores on dependent variable, but subjects will definitely change because of start with extreme)
-selection biases (comparisons have no meaning unless the groups are comparable at start of experiment)
-experimental mortality (subjects lose interest)
-demoralization (feelings of deprivation within the control group may result in giving up)
external validity
possibility that conclusions drawn from experimental results may not be generalizable to the ‘real’ world
-if there’s interaction between testing situation and experimental stimulus
Solomon four-group design
adresses the problem of testing interaction with the stimulus. It avoids the risk that pretesting will have an effect on subjects
controlled experiment
taking action and observing the consequences of that action
natural experiments
experiments which occur in the regular course of social events
pretesting
measurement of a dependent variable among subjects before exposure to stimulus representing an independent variable
post testing
re-measurement of dependent variable among subjects after they have been exposed to a stimulus representing an independent variable
double-blind experiment
neither subjects nor experimenters know which is experimental group and which is control group
randomization
assigning experimental subject and control group randomly
matching
having group of subjects with similarities and splitting them up in experimental and control group
one shot study
single group used for measuring dependent variable
one group pre-test/post-test design
possible that some other factor than independent variable might cause a change between the pre-test and post-test results
static-group comparison
shows one thing to one group but not to another group and then measures the same variable in one group
internal validity
possibility that the conclusions drawn from experimental results may not accurately reflect what went on in the experiment itself
-history (historical event)
-maturation (growing of subjects)
-testing (process of testing influence’s people behaviour)
-instrumentation (giving different questions to each group)
-statistical regression (if you start with extreme, subjects will most likely change)
-selection biases (comparisons have no meaning unless the groups are comparable at start of experiment)
-experimental mortality (people not wanting to participate anymore)
-demoralization (feelings of deprivation within the control group
external invalidity
conclusions drawn from experimental results may not be generalizable to the ‘real’ world
solomon four group design
addresses the problem of testing interaction with the stimulus, it avoids risks that pretesting will have an effect on subjects
group 1- posttest prejudice should be less than pretest prejudice
group 2 - prejudice should be the same in the pretest and posttest
group 1 posttest should show less prejudice than the group 2 posttest does
group 3 posttest should show less prejudice than the group 4 posttest does
group 2 and 4 are control group
post-test-only group design
randomized assignment of subject to experimental and control groups (only group 3 and 4 of Solomon, without pretest)
weakness of experiments
artificiality: what happens in experiment may not reflect what happens in outside world, strengths: isolation of independent variable
ethics in experiments
involve deceiving subjects, intrusive, cause damage to subjects
