R help - Feb 2024 - Interactions in regression

I have no real idea what you are trying to do, but if a table is
what you want, you can probably get it using the table() function.
Or, more likely, the xtabs() function.

Using your example from an earlier post (adjusted to make it
comprehensible to the human mind):

set.seed(1000)
time      <- factor(rep(c("Pre","Post"),each=200))
treatment <-
factor(rep(rep(c("Control","Treatment"),each=100),2))
mu        <- rep(rep(1:2,each=100),2)
response  <- rnorm(400,mean=mu)
xmpldata  <- data.frame(time=time,treatment=treatment,response)
mod       <- lm(response~time*treatment,data=xmpldata)
yhat      <- fitted(mod)
xtb       <- with(xmpldata,xtabs(yhat ~ time+treatment))

print(xtb)
>       treatment
> time     Control Treatment
>   Post  94.10501 201.99112
>   Pre  101.63792 210.04248
Is that (something like) what you want?

cheers,

Rolf Turner

P.S. You said:  "I usually use GUI software".  Now *there* lies your
problem.  A GUI is a black box that removes all control over what is
going on, from your hands.

R. T.




-- 
Honorary Research Fellow
Department of Statistics
University of Auckland
Stats. Dep't. (secretaries) phone:
         +64-9-373-7599 ext. 89622
Home phone: +64-9-480-4619

Hi Rolf,
No it is not.
I don't know to which question did you want to respond ?
I desribed everything in my first email and  attached links from SO with
pictures included, which are quite understandable.

Cheers,
Jacek

wt., 27 lut 2024 o 02:29 Rolf Turner <rolfturner at posteo.net>
napisa?(a):
>
> I have no real idea what you are trying to do, but if a table is
> what you want, you can probably get it using the table() function.
> Or, more likely, the xtabs() function.
>
> Using your example from an earlier post (adjusted to make it
> comprehensible to the human mind):
>
> set.seed(1000)
> time      <- factor(rep(c("Pre","Post"),each=200))
> treatment <-
factor(rep(rep(c("Control","Treatment"),each=100),2))
> mu        <- rep(rep(1:2,each=100),2)
> response  <- rnorm(400,mean=mu)
> xmpldata  <- data.frame(time=time,treatment=treatment,response)
> mod       <- lm(response~time*treatment,data=xmpldata)
> yhat      <- fitted(mod)
> xtb       <- with(xmpldata,xtabs(yhat ~ time+treatment))
>
> print(xtb)
>
> >       treatment
> > time     Control Treatment
> >   Post  94.10501 201.99112
> >   Pre  101.63792 210.04248
>
> Is that (something like) what you want?
>
> cheers,
>
> Rolf Turner
>
> P.S. You said:  "I usually use GUI software".  Now *there* lies
your
> problem.  A GUI is a black box that removes all control over what is
> going on, from your hands.
>
> R. T.
>
>
>
>
> --
> Honorary Research Fellow
> Department of Statistics
> University of Auckland
> Stats. Dep't. (secretaries) phone:
>          +64-9-373-7599 ext. 89622
> Home phone: +64-9-480-4619
>
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