Methodology Review

Question	Answer
Independent variable	Any variable that is systematically varied (manipulated) by the researcher. Question always asked is: Does IV affect/cause DV?
Dependant variable	Any variable that is measured or observed. Question always asked is: Does IV affect/cause DV?
Extraneous variable	Any variable that is not the IV but may affect the DV. Affects internal validity (as it weakens an valid inference of IV on DV).
Negative effects of extraneous variables	Makes it harder to see effects of IV by adding variability ("error" or "noise"). If correlated with IV (confounding variable) makes it impossible to determine true effects on IV on DV.
Eliminate extraneous variables by:	Eliminate (outside noise). Hold constant. Measure and include in analysis. Randomise allocation in groups.
Random Allocation	Is the only method that allows for control of thousands of extraneous variables that researchers don't know about and can't measure. Without it researchers can never be sure whether difference observed is might be due to a confounding variable. It "unconfounds" by ensuring there is no systematic differences between groups. It doesn't eliminate

Resource summary

	Created by Cynthia Tran about 7 years ago