```Date: Wed, 2 May 2007 09:58:36 -0500 Reply-To: "Swank, Paul R" Sender: "SPSSX(r) Discussion" From: "Swank, Paul R" Subject: Re: How to graph an interaction with covariates Comments: To: Stephen Salbod In-Reply-To: <000601c78c47\$f4da43a0\$de8ecae0\$@edu> Content-Type: text/plain; charset="us-ascii" Yes. We typically use the mean of the covariate when graphing interactions of other terms. But whne the covariate is dichotomous, it really doesn't make sense to use the mean. Using one level or the other is more fitting. The zero term of course is the easiest to use. Paul R. Swank, Ph.D. Professor Director of Reseach Children's Learning Institute University of Texas Health Science Center-Houston -----Original Message----- From: SPSSX(r) Discussion [mailto:SPSSX-L@LISTSERV.UGA.EDU] On Behalf Of Stephen Salbod Sent: Tuesday, May 01, 2007 6:25 PM To: SPSSX-L@LISTSERV.UGA.EDU Subject: How to graph an interaction with covariates Good Evening, How do I deal with covariates when I want to graph a significant interaction (regression analysis). I want to graph a 2-way interaction where the outcome is continuous and the two predictors are continuous and dichotomous, respectively. Also include in the analysis were ten covariates: eight dichotomous (0,1) and two continuous. What I have done is set the dichotomous variables equal to 0 and use the mean for the two continuous variables; that is, I add the weighted means of the two continuous variables to the constant. I then proceeded follow the steps outline in Jaccard et al (1990) and Aiken and West (1991) to generate plot points. My question is: Did I handle the covariates correctly? Any advice will be greatly appreciated. Thank you, Stephen Salbod, Pace University, NYC ```

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