SPSS: Interaction of a covariate and factor

[Talk Stats]

Hi,

After I have found that the interaction between a covariate and factor is
significant, I would like to know if each level of the factor has a
significant interaction term with the covariate, or if only one of the
levels is different than the other two in terms of the interaction term.

I can't figure out how to do this in SPSS. It appears that I need to write
a contrast script, but I can't create a contrast for a covariate, and the
resulting output does not display the interaction effect.

Any ideas would be greatly appreciated. I've attached my code below.
Thanks.
Sincerely,
Jon

Notes: JND is the dependent, Baseline is the covariate, Location is the
factor.
UNIANOVA
JND WITH Baseline BY Location
/CONTRAST (Location)=special(-2 1 1, 1 -2 1, 1 1 -2)
/METHOD = SSTYPE(3)
/INTERCEPT = EXCLUDE
/CRITERIA = ALPHA(.05)
/DESIGN = Baseline Location Baseline by Location.

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http://www.talkstats.com/showthread.php?t=3432

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[Zdaniuk, Bozena-2]

Hello, assuming you are running your analysis using GLM, please use the following subcommand:
  /PRINT = DESCRIPTIVE PARAMETER
The keyword PARAMETER will print out the regression coefficients for covariate-outcome separately for each level of the factor variable and you can see where your interaction is coming from. Let me know if you have any additional questions about it.
Bozena

Bozena Zdaniuk, Ph.D.
University of Pittsburgh
UCSUR, 6th Fl.
121 University Place
Pittsburgh, PA 15260
Ph.: 412-624-5736
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Email: [hidden email]


-----Original Message-----
From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of Talk Stats
Sent: Thursday, February 21, 2008 10:59 AM
To: [hidden email]
Subject: SPSS: Interaction of a covariate and factor

Hi,

After I have found that the interaction between a covariate and factor is
significant, I would like to know if each level of the factor has a
significant interaction term with the covariate, or if only one of the
levels is different than the other two in terms of the interaction term.

I can't figure out how to do this in SPSS. It appears that I need to write
a contrast script, but I can't create a contrast for a covariate, and the
resulting output does not display the interaction effect.

Any ideas would be greatly appreciated. I've attached my code below.
Thanks.
Sincerely,
Jon

Notes: JND is the dependent, Baseline is the covariate, Location is the
factor.
UNIANOVA
JND WITH Baseline BY Location
/CONTRAST (Location)=special(-2 1 1, 1 -2 1, 1 1 -2)
/METHOD = SSTYPE(3)
/INTERCEPT = EXCLUDE
/CRITERIA = ALPHA(.05)
/DESIGN = Baseline Location Baseline by Location.

--
This question was originally posted at:
http://www.talkstats.com/showthread.php?t=3432

=====================
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[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command
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[Jamie Burnett-3]

Hi,
I would like to run a multinomial logistic regression in SPSS version
15, but unlike the binary logistic option I don't seem to be able to
tell SPSS which level of each of my independent categorical variables I
would like to use as the reference category. Is there anyway of doing
this?
Many Thanks

Jamie


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