Date: Tue, 20 Mar 2001 14:26:13 -0600
Reply-To: Sonya Premeaux <premeaux@MAIL.MCNEESE.EDU>
Sender: "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From: Sonya Premeaux <premeaux@MAIL.MCNEESE.EDU>
Subject: Re: plotting interactions
Content-Type: text/plain; charset="iso-8859-1"
Thanks for your quick response.
This is not exactly what I am looking for, but is close. I need each IV on
a separate chart, i.e., TR on a chart, TM on a chart, SE on a chart, as the
horizontal axis. Then, I need 2 lines on each chart, one for high SM and
one for low SM. The y axis would be my dependent variable, SU. The data in
the example are purely hypothetical.
I can split the file into high and low SM and run the regression, saving my
predicted values. When I do the scatter diagram, however, I get two plots,
one for high SM and one for low SM. How do I get these on the same chart?
Also, how do I change the color of the markers?
----- Original Message -----
From: "Hector E. Maletta" <hmaletta@overnet.com.ar>
To: "Sonya Premeaux" <premeaux@mail.mcneese.edu>
Cc: <SPSSX-L@LISTSERV.UGA.EDU>
Sent: Tuesday, March 20, 2001 11:54 AM
Subject: Re: plotting interactions
> Sonya,
> one possible way is to plot the regression of your dependent variable
> against the predicted value (from an equation containing only your
> independent variables TR and TM), split by your moderating variable SM.
> This would give you only one chart, with two sets of points (one color
> for low SM, another for high SM). You can show the regression lines for
> both sets, and get the points hidden with a suitable choice of marker or
> color.
>
> The steps for this are as follows:
> 1. Create SMBINARY with values 1 and 2 for high and low SM.
> 2. Choose SPLIT FILE BY SMBINARY.
> 3. Do a REGRESSION of SU with TR and TM as indep.variables. Choose to
> save the predicted values as a new variable, say SUPRED.
> 4. Cancel the SPLIT FILE setting.
> 5. Do a scatter diagram of SU by SUPRED, split by SMBINARY.
> 6. Edit the graph. In the editor, choose to show the regression lines
> and edit the color/markers to hid the points, so that only the lines are
> visible. Alternatively you can keep the points visible, but this may
> result in a confusing graph if the points are many (remember they are
> from two sets, represented by two colors/markers).
> The resulting regression lines will show the effect of the moderating
> variable SM. The line with low SM, I suppose, will have a steeper slope,
> if SM plays a moderating influence.
> Hope this helps.
>
> Hector Maletta
> Universidad del Salvador
> Buenos Aires, Argentina
>
> Sonya Premeaux wrote:
> >
> > This is a multi-part message in MIME format.
> >
> > ------=_NextPart_000_0029_01C0B130.4A3E0920
> > Content-Type: text/plain;
> > charset="iso-8859-1"
> > Content-Transfer-Encoding: quoted-printable
> >
> > I need to plot interaction effects for a regression. Can anyone help?
=
> > My data looks something like this:
> >
> > SM SU TR TM SE
> > 1 1 1 1 1
> > 2 2 2 2 2 =20
> >
> > My dep variable is SU. SM is a moderator of the relationships between =
> > SU and the other variables. I want to split SM into High and Low and =
> > plot regression equations. I would end up with 2 regression equations =
> > on each chart so that my dep variable is on my Y axis, one of the IVs is
=
> > on the X axis and there is a regression line for high SM and low SM. =
> > Can this be done? If so, how? If not, any suggestions on how to do it
=
> > elsewhere? Thanks.
> >
> > ------=_NextPart_000_0029_01C0B130.4A3E0920
> > Content-Type: text/html;
> > charset="iso-8859-1"
> > Content-Transfer-Encoding: quoted-printable
> >
> > <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
> > <HTML><HEAD>
> > <META content=3D"text/html; charset=3Diso-8859-1" =
> > http-equiv=3DContent-Type>
> > <META content=3D"MSHTML 5.00.2919.6307" name=3DGENERATOR>
> > <STYLE></STYLE>
> > </HEAD>
> > <BODY bgColor=3D#ffffff>
> > <DIV><FONT size=3D2>I need to plot interaction effects for a =
> > regression. Can=20
> > anyone help? My data looks something like this:</FONT></DIV>
> > <DIV> </DIV>
> > <DIV><FONT size=3D2>SM SU =
> > TR =20
> > TM SE</FONT></DIV>
> > <DIV><FONT size=3D2>1 =20
> > 1 =
> > 1 =20
> > 1 1</FONT></DIV>
> > <DIV><FONT size=3D2>2 =20
> > 2 =20
> >
2 2  =
> > ; =20
> > 2 </FONT></DIV>
> > <DIV> </DIV>
> > <DIV> </DIV>
> > <DIV><FONT size=3D2>My dep variable is SU. SM is a moderator of =
> > the=20
> > relationships between SU and the other variables. I want to =
> > split SM=20
> > into High and Low and plot regression equations. I would end up =
> > with 2=20
> > regression equations on each chart so that my dep variable is on my Y =
> > axis, one=20
> > of the IVs is on the X axis and there is a regression line for high SM =
> > and low=20
> > SM. Can this be done? If so, how? If not, any =
> > suggestions on=20
> > how to do it elsewhere? Thanks.</FONT></DIV></BODY></HTML>
> >
> > ------=_NextPart_000_0029_01C0B130.4A3E0920--
>
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