Date:         Wed, 8 Jul 2009 12:31:50 -0400
Reply-To:     "FRESCO, DAVID" <fresco@kent.edu>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         "FRESCO, DAVID" <fresco@kent.edu>
Subject:      Converting t to Cohen's d
Content-Type: multipart/alternative;

Colleagues,

I am trying to determine the appropriate equation to convert a paired sample t-test to Cohen's d.

Rosenthal and Rosnow have published the equation of d = 2t/SQRT(df), which I thought was encompassing of all kinds of t tests.

I recently read a paper that for a paired sample t-test another equation attributed to Rosenthal was as follows: d = t/SQRT(df).

Can some kind soul point me in the direction of sources and arguments for one or the other or perhaps something totally different.  CC'ing my email to replies would be appreciated as I only take the digest of this listserve.

Thanks.

David Fresco
------

David M. Fresco, Ph.D.               fresco@kent.edu
Department of Psychology        Voice:  (330) 672-4049
Kent State University                   Fax:    (330) 672-3786
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