Hi
On 12 Mar 2001, Radford Neal wrote:
> Yes indeed. And the context in this case is the question of whether
> or not the difference in performance provides an alternative
> explanation for why the men were paid more (one supposes, no actual
> salary data has been released).
>
> In this context, all that matters is that there is a difference. As
> explained in many previous posts by myself and others, it is NOT
> appropriate in this context to do a significance test, and ignore the
> difference if you can't reject the null hypothesis of no difference in
> the populations from which these people were drawn (whatever one might
> think those populations are).
Personally, I am not interested in the question of statistical
testing to dismiss the alternative explanation being proposed;
indeed, I suspect that the original claim about gender being the
cause of salary differences would not stand up very well either
to statistical tests. But there does seem to me to be more than
just saying ... "see there is a difference" and that statistical
procedures would have a role to play. For example, wouldn't the
strength and consistency of the differences influence your
confidence that this was indeed the underlying factor? The same
difference in means due to one or two outliers would surely not
mean the same thing as a uniform pattern of productivity
differences, would it? And wouldn't you want to demonstrate that
there was a significant and ideally strong within-group
relationship between productivity and salary before claiming that
it is a reasonable alternative for the between-group differences?
Or at least, wouldn't that strengthen the case? I appreciate
that in some domains (e.g., intelligence testing), people are
reluctant to make inferences about between-group differences on
the basis of within-group correlations, but that is the basic
logic of ANCOVA and related methods.
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
============================================================================
=================================================================
Instructions for joining and leaving this list and remarks about
the problem of INAPPROPRIATE MESSAGES are available at
http://jse.stat.ncsu.edu/
=================================================================
