On Wed, 5 Dec 2001, Karl L. Wuensch wrote: <much stuff snipped> > > > So why is it that many persons believe that one can make causal inferences >with confidence from the results of two-group t tests and ANOVA but not with the >results of correlation/regression techniques. I believe that this delusion stems >from the fact that experimental research typically involves a small number of >experimental treatments that data from such research are conveniently evaluated with >two-group t tests and ANOVA. Accordingly, t tests and ANOVA are covered when >students are learning about experimental research. Students then confuse the >statistical technique with the experimental method. I also feel that the use of the >term "correlational design" contributes to the problem. When students are taught to >use the term "correlational design" to describe nonexperimental methods of collecting >data, and cautioned regarding the problems associated with inferring causality from >such data, the students mistake correlational statistical techniques with "correla! tional" data collection methods. I refuse to use the word "correlational" when describing a design. I much prefer "nonexperimental" or "observational."
I have notice the same tendency to confuse the correlation coefficient with observational data collection methods. I explain to my students that the confusion comes from exactly the types of things that Karl describes. Historically regression has been taught in the context of observational research and ANOVA in the context of experimental research. (Kirk's book about ANOVA designs is even entitled "Experimental Design".) This simplifies things for the learner, but can lead them down exactly the wrong path when it comes to analyzing/interpreting their data later in life. We really need to emphasize over and over that it is the manner in which you collect the data and not the statistical technique that allows one to make causal inferences. Michael > > > > > -------------------------------------------------------------------------------- > > Karl L. Wuensch, Department of Psychology, > East Carolina University, Greenville NC 27858-4353 > Voice: 252-328-4102 Fax: 252-328-6283 > [EMAIL PROTECTED] > http://core.ecu.edu/psyc/wuenschk/klw.htm > > > ******************************************************************* Michael M. Granaas Associate Professor [EMAIL PROTECTED] Department of Psychology University of South Dakota Phone: (605) 677-5295 Vermillion, SD 57069 FAX: (605) 677-6604 ******************************************************************* All views expressed are those of the author and do not necessarily reflect those of the University of South Dakota, or the South Dakota Board of Regents. ================================================================= Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =================================================================
