Here are more details on the hypothesis test of no effect, which for the 
sophisticated reader will provide the same information provided by the 
confidence interval on d, but, IMHO, not for the naive reader (that is, most 
consumers of and many producers of behavioral research).

A.  n1 = 2, n2 = 2, t(2) = 4.25, p = .0512.  Using the SPSS script at 
http://core.ecu.edu/psyc/wuenschk/SPSS/CI-d-SPSS.zip or the SAS program at 
http://core.ecu.edu/psyc/wuenschk/SAS/Conf-Interval-d2.sas , g (point 
estimate of Cohen's d) = 4.25 and a 95% confidence interval on d runs 
from -.0135 to 8.5415.  Yes, I purposely chose a small sample size and a big 
point estimate of effect, better to illustrate my point.

B. n1 = 5000, n2 = 5000, t(9998) = 1.95, p = .0512, g = .039, and the 
confidence interval for d runs from -.0002 to .0782.
----- Original Message ----- 
From: "Paul Smith" <[EMAIL PROTECTED]>
To: "Teaching in the Psychological Sciences" <[email protected]>
Sent: Saturday, June 25, 2005 11:23 AM
Subject: Re: p = .051


Could you comment on how this comparison would look to you if instead of
just the p-value from the hypothesis test, you also included a measure
of effect size?

This is a very interesting discussion. Thanks,

Paul Smith

Karl L. Wuensch wrote:
>   My point is that the CI gives you everything you get with the hypothesis
> test and more.



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