At 09:21 AM 2/13/02 -0600, Mike Granaas wrote: >On Fri, 8 Feb 2002, Thomas Souers wrote: > > > > 2) Secondly, are contrasts used primarily as planned comparisons? If > so, why? > > > >I would second those who've already indicated that planned comparisons are >superior in answering theoretical questions and add a couple of comments:
another way to think about this issue is: what IF we never had ... nor will in the future ... the overall omnibus F test? would this help us or hurt us in the exploration of the experimental/research questions of primary interest? i really don't see ANY case that it would hurt us ... and, i can't really think of cases where doing the overall F test helps us ... i think mike's point about planning comparisons making us THINK about what is important to explore in a given study ... is really important because, we have gotten lazy when it comes to this ... we take the easy way out of testing all possible paired comparisons when, it MIGHT be that NONE of these are really the crucial things to be examined Dennis Roberts, 208 Cedar Bldg., University Park PA 16802 <Emailto: [EMAIL PROTECTED]> WWW: http://roberts.ed.psu.edu/users/droberts/drober~1.htm AC 8148632401 ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at http://jse.stat.ncsu.edu/ =================================================================
