Maybe someone will point me to other newsgroups or mail groups on biological or clinical statistics as I know that sci.stat.edu is about the education of statistics not really about stats itself..
My question (frustration, rather) is: how do you deal with the fact that signs on coefficients of multivariable models change direction and size when you remove a predictor of the dependant variable(s). is there a test for this? It seems to me that if genetics place an important part in determining cholesterol levels (say), and you study diet as it relates to cholesterol, but forget to insert genetics (say in a twin study), then you might find that eating eggs raises your cholesterol whereas if you don't include eggs might lower cholesterol. (hyopthetial) How do observational and especially exploratory studies overcome this problem? I think you can only overcome it (given lack of theoretical grounds to overcome it) by looking at the size of the relationship and "guess" at how true your result is, even though the opposite of your result might be what happens in real life. . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
