Date:         Tue, 6 Dec 2005 12:21:15 -0600
Reply-To:     "Swank, Paul R" <Paul.R.Swank@uth.tmc.edu>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         "Swank, Paul R" <Paul.R.Swank@uth.tmc.edu>
Subject:      Re: Significance testing between R-square from linear and
              R-square              from curvilinear regression (Revised).
Content-Type: text/plain; charset="us-ascii"

Steiger's multicor program will do that.

"Want to compare multiple, partial, or canonical correlations for
equality?
Steiger and Browne (1984) show how you can do this by reprasing the
hypothesis as a pattern hypothesis testable by MULTICORR. For a recent
review of some related correlational tests, see Olkin and Finn (1995).
References
Olkin, I., and Finn, J.D. (1995). Correlations redux. Psychological
Bulletin, 118, 155-164.
Steiger, J.H. (1979). Multicorr: a computer program for fast, accurate,
small-sample tests of correlational pattern hypotheses. Educational and
Psychological Measurement, 39, 677-680.
Steiger, J.H. (1980). Tests for comparing elements of a correlation
matrix. Psychological Bulletin, 87, 245-251.
Steiger, J.H., & Browne, M.W. (1984). The comparison of interdependent
correlations between optimal linear composites. Psychometrika, 49,
11-21. "


Paul R. Swank, Ph.D.
Professor, Developmental Pediatrics
Director of Research, Center for Improving the Readiness of Children for
Learning and Education (C.I.R.C.L.E.)
Medical School
UT Health Science Center at Houston

-----Original Message-----
From: SPSSX(r) Discussion [mailto:SPSSX-L@LISTSERV.UGA.EDU] On Behalf Of
Sungeun Chung
Sent: Tuesday, December 06, 2005 11:18 AM
To: SPSSX-L@LISTSERV.UGA.EDU
Subject: Significance testing between R-square from linear and R-square
from curvilinear regression (Revised).

 Hi, I want to clarify my question in previous question.

I have two variables,  X: time (11 time points) and Y: means of
evaluation (one group, N = 132).

I expect that exponential function will fit better than a linear
function to predict the trajectory.

I did a curve estimation with exponential function and found R-square
from the exponential  function is greater than R-square from a linear
function.
But how can I test if the difference in R-squares is signifcant?

I found a formular in Blalock (1972). But it requires correlation
between Y and transformed Y.

Should I do time series analysis?

Any help will be greately appreciated.  Thanks in advance,

Sungeun

-
Sungeun Chung, Ph.D.

Assistant Professor
Department of Communication
Memorial Hall 303G
Western Illinois University
Macomb, IL 61455-1390
Tel. (309) 298-2219
E-mail: S-Chung@wiu.edu; chseun21@yahoo.com