Date: Fri, 23 Sep 2005 20:14:45 0400
ReplyTo: Stephen Salbod <ssalbod@pace.edu>
Sender: "SPSSX(r) Discussion" <SPSSXL@LISTSERV.UGA.EDU>
From: Stephen Salbod <ssalbod@pace.edu>
Subject: GLM Repeated with Categorical Covariates
ContentType: text/plain; charset="usascii"
A Friday question: I want to us ethnicity (4 levels) as a covariate in an
ANCOVA procedure. I think the code is correct, but since I've never worked
with a set, as covariate, I'm a little concerned. The Syntax Guide had
little to say on this issue (see GLM: Repeated Measures, 726734).
COMPUTE Ethnic1 = 0.
COMPUTE Ethnic2 = 0.
COMPUTE Ethnic3 = 0.
DO IF (Ethnic EQ 1).
 COMPUTE Ethnic1 = 1.
ELSE IF (Ethnic EQ 2).
 COMPUTE Ethnic2 = 1.
ELSE IF (Ethnic EQ 3).
 COMPUTE Ethnic3 = 1.
END IF.
GLM
pretest posttest BY group WITH ethnic1 ethnic2 ethnic3
/WSFACTOR = time 2
/METHOD = SSTYPE(3)
/EMMEANS = TABLES(group*time) WITH(ethnic1=MEAN ethnic2=MEAN ethnic3=MEAN)
/CRITERIA = ALPHA(.05)
/WSDESIGN = time
/DESIGN = ethnic1 ethnic2 ethnic3 group .
Any suggestions will be most welcome.
TIA.
Stephen Salbod, Pace University, NYC
