An observational study records explanatory and response variables without assigning treatments to the subjects. Such a study can reveal an association, but because confounding variables may be present, an association alone does not establish causation.
Observational Study
See also
Confounding Variable, Experiment, Experimental Design, Lurking Variable, Random AssignmentExplore with Wolfram|Alpha
References
Moore, D. S. and McCabe, G. P. Introduction to the Practice of Statistics, 4th ed. New York: W. H. Freeman, 2002.Cite this as:
Weisstein, Eric W. "Observational Study." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/ObservationalStudy.html