Making various mixed effects models

I've tried to create three models (using R): an intercept only linear regression, a simple mixed effects regression and a by-subject effects mixed effects regression.

An intercept only regression models the grand mean of a response variable plus error. In mtcars, the variable drat may be considered a response variable. In the model below, have I correctly modelled the grand mean of drat, plus error?

interceptOnly <- lm(drat ~ 1, data=mtcars)

A simple mixed effects regression models the grand mean of a response variable, plus subject deviation, plus error. In mtcars, drat may be considered a response variable and cyl a subject deviation. In the model below, have I correctly modelled the grand mean of drat, plus the deviation of cyl from drat, plus error?

library(lme4)
simpleMixedEffects <- lmer(drat ~ (1|cyl), data=mtcars)

A by-subject effects mixed effects regression models the grand mean of a response variable, plus subject deviation, plus condition effect, plus error. In mtcars, drat may be considered a response variable, cyl a subject deviation and wt a condition effect. In the model below, have I correctly modelled the grand mean of drat, plus the deviation of cyl from drat, plus the effect of wt, plus error?

bySubjectMixedEffects <- lmer(drat ~ (1|cyl) + wt, data=mtcars)

I have one further question:

How can I model a by-subject varying condition effect model. This is a mixed effects model which models the grand mean of a response variable, plus group deviation from grand mean (random effect), plus condition effect (fixed effect), plus group deviation from condition effect (random effect), plus error. Could someone provide R code that outputs a "by-subject varying condition effect model"?

• More edits made. How can I further improve question? – luciano Jun 18 '13 at 10:35
• As you press me, my personal view is that a good acceptable question will just cite the video as a reference and be focused on questions that other people might ask or difficulties others might express. This looks too much like "Here are some examples I have tried; are they correct?" There are many questions on mixed effects on this site; I can't see this being one of the most useful. Also, you are presupposing some acquaintance with a particular dataset, mtcars. – Nick Cox Jun 18 '13 at 10:41
• Question further edited to remove any necessity of familiarity with mtcars dataset. – luciano Jun 18 '13 at 10:51