\begin{Schunk}
\begin{Sinput}
 colM3T <- t(sapply(jumboData, colMeans))
 colM3T[1:5, ]
\end{Sinput}
\begin{Soutput}
     ds       x1       x2
[1,]  1 90.91261 30.94204
[2,]  2 89.98699 34.61032
[3,]  3 87.38849 33.30044
[4,]  4 88.73683 31.78901
[5,]  5 88.99573 33.70151
\end{Soutput}
\end{Schunk}
