Research & Stats Flashcards
Moderator Variable
Affects direction and strength of the relationship between IV and DV.
(mOderator is Outside the relationship of IV and DV)
Mediator Variable
Explains the relationship between IV and DV
(mEdiator Explains the relationship between IV and DV)
Bar graphs
-nominal or ordinal data
-categories on X axis
-percentage / recorded data on the Y axis
Histogram
-Interval or ratio data
-score listed in order on X axis
-number/percentile of the observation on Y axis
Frequency Polygon
-line graph
-interval or ratio data
Normal Distribution
-symmetrical
-central measures of tendency are equal to same value
-68% scores fall within 1 SD
-95% scores fall within 2 SD
-99% scores fall within 3 SD
Positively Skewed
-Tail at the higher end of the X axis
-Mean is largest central tendency
-Mode is smallest central tendency
Negatively Skewed
-Tail at the lower end of the X axis
-Mean is smallest central tendency
-Mode is the largest central tendency
History
Threat to internal validity
-events that occur during the study (effect results)
*Control
-more than 1 group
-random assignment
Maturation
Threat to internal validity
-physical, cognitive and emotional changes that occur in the subjects (due to passage of time).
*Control
-more than 1 group
-random assignment
Differential Selection
Threat to internal validity
-different assignment to treatment groups
-when groups differ at the beginning of the study due to assignment.
*Control
-random assignment
Regression towards the Mean (aka Statistical Regression)
Threat to internal validity
-participants selected for their extreme score on pre-test gradually start to shift towards mean scores later on in the study (post test assessment).
-characteristics assessed for are typically not stable over time.
Testing
Threat to internal validity
-taking a pretest effects later responses
*Control
-no pretest
-Soloman four group design
Instrumentation
Threat to internal validity
-when instrument used to measure IV changes over time.
Differential Attrition
Threat to internal validity
-participants dropout of 1 group
-composition of groups are altered
Reactivity
Threat to external validity
-when participants respond differently to the IV during a study than they would normally.
*Control
-single or double blind study
-deception
-unobtrusive measures
Multiple Treatment Interference
Threat to external validity
-carryover effects and order effects
*Control
-counter balancing (different groups receive different levels of IV)
-Latin Square Design (type of counter balancing)
Selection Treatment Interference
Threat to external validity
-research participants differ from the population of interest.
*Control
-random selection
Pretest Treatment Interactions
Threat to external validity
-when taking a pretest effects how participants respond to the IV.
Soloman Four Group Design
-used to identify the effects of pretesting on a study’s internal and external validity
-4 groups
-2 levels (2 groups exposed to IV, 1 of the 2 groups are given a pretest)
Population validity
External validity
-how generalized are finding to the population participants are pooled from.
Ecological validity
External validity
-how generalized are findings in different settings
Temporal validity
External validity
-how generalized are findings across time
Treatment validity
External validity
-how generalized are finding given variation of the treatment (IV)