\begin{Schunk}
\begin{Sinput}
  attributes(dat)
\end{Sinput}
\begin{Soutput}
$names
[1] "grp" "ed"  "inc" "mar" "sex"

$class
[1] "data.frame"

$row.names
 [1]  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19
\end{Soutput}
\end{Schunk}
