\begin{table}%t6  
\caption{\label{tab:means}Mean values and standard deviations of the low and high frequency 
spectral indices.}
\small%\centerline
 {
\begin{tabular}{lrrrr}
\hline                                     
\hline \noalign{\smallskip}                                   
Sample$^{(a)}$ & $\alpha_{\rm L}$ & $\sigma$ & $\alpha_{\rm H}$ & $\sigma$   \\ 
\hline
ATESP          &  $-0.18$ & (0.11)  & $-0.79$ & (0.16) \\
Massardi G  &  $-0.01$ & (0.08)  & $-0.35$ & (0.09) \\
ATESP + Massardi G far    &  $-0.08$  & (0.07)  & $-0.50$ & (0.08) \\
Massardi Q far     &  $0.21$  & (0.04)  & $-0.16$ & (0.03) \\ 
\hline 
\end{tabular}}
\medskip
$^{(a)}$ ``Massardi G'' and ``Massardi Q'' respectively refer to galaxies and stellar identifications of the Massardi \etal\  sample. ``Far''~refers to $z>0.5$~sources (or~unknown redshift for quasar candidates).
\end{table}