Experimental Research Independent variable Dependent variable Causation
CHAPTER 7 Experimental Research
Establishing causation Universal laws Statistical laws
Requirements for causal relationship IV must precede the DV IV and DV must covary Changes in DV must be result of changes in the IV
Control – a researcher attempts to exclude other possible causes of the effect he/she is studying
Exposing participants to the IV Conditions Treatment Attribute variables
Selection equivalence
Random assignment increases the internal validity of a study while random sampling increases external validity of a study
Controlling for the effects of extraneous influences Threshold effects Experimenter effects Other effects
Experimental Research Designs Full experiment Quasi-experiment Preexepriment
Factorial design Studies with more that 1 IV are summarized with a design statement Example a 2 x2 design
Between-group design Within-group design
Lab versus field experiments