Hi On Mon, 11 Nov 2002, Rob Flint wrote:
> One of my students doing her senior thesis ran her stats and got results of > .056 and .08 for two different ANOVAs. In the past I have seen published > studies indicating that these are "marginally significant." How do you deal > with results of this nature? More importantly, do you have any citations > (journals or books) that discuss the value of including/discussing results > that seem to "approach significance"? Unlike some others who have responded, I do not see significance as an either-or proposition. Indeed, APA style now calls for the reporting of p-values, rather than dichotomous judgments, presumably on the grounds that a p of .056 or even .08 might or might not be meaningful to readers. Nor do I read "approaching" as meaning moving in the direction of significance, although that is certainly one interpretation. I always took it as synomymous with marginal (i.e., close to some arbitrary cut-off). None of the responses that I saw raised the issue of directional vs. non-directional tests (i.e., one- vs. two-tailed ps). Are these ps for non-directional tests in a study where a more knowledgeable researcher might have predicted the direction of difference on the basis of theory or past research. A second issue is how many df were associated with the numerator of the F ratios? If the df are >1 then I would view them more positively, especially if the "predicted" effect could readily be translated into a single df contrast. Another important (and related) question is whether the ps are for interactions. ANOVAs are quite insensitive when it comes to interactions (i.e., lack power) and I would certainly look favorably on a (perhaps-expected) interaction with a p of .056 or .08 (e.g., doing simple effects analyses or partitioning the interaction). So before answering this question, I would like to see the actual variables and levels involved, the theoretical relationships predicted, and (related to people's concern with power) the n's for the conditions/cells. Best wishes Jim ============================================================================ James M. Clark (204) 786-9757 Department of Psychology (204) 774-4134 Fax University of Winnipeg 4L05D Winnipeg, Manitoba R3B 2E9 [EMAIL PROTECTED] CANADA http://www.uwinnipeg.ca/~clark ============================================================================ --- You are currently subscribed to tips as: [EMAIL PROTECTED] To unsubscribe send a blank email to [EMAIL PROTECTED]
