\begin{Schunk}
\begin{Sinput}
 m7trouble <- lm(log(prestige) ~ as.numeric(education) + as.factor(type), data=Prestige)
 colnames( model.frame(m7trouble) )
\end{Sinput}
\begin{Soutput}
[1] "log(prestige)"         "as.numeric(education)" "as.factor(type)"      
\end{Soutput}
\end{Schunk}
