Vassar Stats has an online procedure for this at:
 
http://faculty.vassar.edu/lowry/rdiff.html
 
Rick
 
 
Dr. Rick Froman
Psychology Department
Box 3055
John Brown University
Siloam Springs, AR 72761
(479) 524-7295
[EMAIL PROTECTED]
"Pete, it's a fool that looks for logic in the chambers of the human heart"
- Ulysses Everett McGill

________________________________

From: Rickabaugh, Cheryl [mailto:[EMAIL PROTECTED]
Sent: Sun 11/4/2007 7:23 PM
To: Teaching in the Psychological Sciences (TIPS)
Subject: RE: Comparing correlations



Hi, Marie. 

I rely on Bob Rosenthal for answering that question. It's essentially the same 
thing as comparing effect sizes reported as correlations. Transform your raw rs 
to Fisher z(sub)r. Z of difference is zr1 minus zr2 divided by the square root 
of 1 over N1-3 plus 1 over N2-3). I use Chapter 21 of Rosenthal & Rosnow's 
Essentials of Behavioral Research as a quick reference. It also contains the 
table for finding your Zr (though Excel will do the same).

HTH, 
Cheryl R. 
--- 
Cheryl A. Rickabaugh 
University of Redlands 


-----Original Message----- 
From: Helweg-Larsen, Marie [mailto:[EMAIL PROTECTED] 
Sent: Sun 11/4/2007 5:02 PM 
To: Teaching in the Psychological Sciences (TIPS) 
Subject: Comparing correlations 
  
Hi Tipsters 

I have a simple correlational question. What is the formula for comparing two 
significant correlation coefficients? Among one group r(44) = .37, p = .01 and 
among a different group  r(115) = .19, p = .04. My question is whether the 
first corr is sig. greater than the second?

Marie 




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