[R] User error in calling predict/model.frame

[Ista Zahn]

Another option is


set.seed(10)
dat <- data.frame(xxA = rnorm(20,10), xxB = rnorm(20,20))
dat$out <- with(dat,xxA+xxB+xxA*xxB+rnorm(20,20))

lm.mod <- lm(out ~ I(scale(xxA))*I(scale(xxB)), data=dat)
newdata <- data.frame(xxA=c(-1,0,1),xxB=c(-1,0,1))
preds <- predict(lm.mod, newdata)

Best,
Ista


On Sat, Jan 29, 2011 at 5:12 PM, Russell Pierce <rpier001 at ucr.edu> wrote:
> Just in case someone else stumbles onto this thread and is facing a
> similar issue:  The quick solution for me turned out to be using Glm
> and Predict in the rms package.  Thanks go to Joshua and Ista for
> helping me out with this issue.  Double thanks go to Joshua for
> suggesting I take a closer look at the rms package.
>
> library(rms)
> dat <- data.frame(xxA = rnorm(20,10), xxB = rnorm(20,20))
> dat$out <- with(dat,xxA+xxB+xxA*xxB+rnorm(20,20))
> rms.res <- Glm(out ~ scale(xxA)*scale(xxB),data=dat)
> newdata <- as.data.frame(Predict(rms.res,xxA=c(-1,0,1),xxB=c(-1,0,1))[,1:3])
>
> -----------------------------------
> Russell S. Pierce, M.A.
> Visual Cognition Lab
> Department of Psychology
> University of California, Riverside
> 900 University Avenue
> Riverside, CA 92521
> Lab Phone: (951) 827-7399
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org