i would say that karl has demonstrated that IF we know conditions of manipulation or not ... we can have a better or lesser idea of what (if anything) impacted (caused?) what
that i will grant him to argue that r or eta has anything to do with this ... i would respectfully disagree they are just byproducts of our manipulations ... one cannot equate the byproducts with THE manipulations .. At 03:23 PM 12/6/01 -0500, Wuensch, Karl L wrote: > My experimental units are 100 classrooms on campus. As I walk into >each room I flip a perfectly fair coin in a perfectly fair way to determine >whether I turn the room lights on (X = 1) or off (X = 0). I then determine >whether or not I can read the fine print on my bottle of smart pills (Y = 0 >for no, Y = 1 for yes). From the resulting pairs of scores (one for each >classroom), I compute the phi coefficient (which is a Pearson r computed >with dichotomous data). Phi = .5. I test and reject the null hypothesis >that phi is zero in the population (using chi-square as the test statistic). >Does correlation (phi is not equal to zero) imply causation in this case? >That is, can I conclude that turning the lights on affects my ability to >read fine print? could be here that if you did not have glasses ... you could not have read anything with or without light ... and, since you did have glasses ... the r you get is because of the implicit interaction between light or not, and glasses or not > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >Karl L. Wuensch, Department of Psychology, >East Carolina University, Greenville NC 27858-4353 >Voice: 252-328-4102 Fax: 252-328-6283 >mailto:[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> >http://core.ecu.edu/psyc/wuenschk/klw.htm ><http://core.ecu.edu/psyc/wuenschk/klw.htm> > > > >================================================================= >Instructions for joining and leaving this list and remarks about >the problem of INAPPROPRIATE MESSAGES are available at > http://jse.stat.ncsu.edu/ >================================================================= _________________________________________________________ dennis roberts, educational psychology, penn state university 208 cedar, AC 8148632401, mailto:[EMAIL PROTECTED] http://roberts.ed.psu.edu/users/droberts/drober~1.htm ================================================================= Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =================================================================
