Is it legal to test for an interaction without testing for the main effects of the variables included in those interactions. And, in the case it is (which I recall it isn't), does one still have to account for the degrees of freedom used by the non-tested main effects?
Hoping that was sufficiently clear, Art . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
