\begin{table}%t3
\caption{\label{t3}Mean and mode of the metallicity distributions, and  the metallicity range that includes 66$\%$ of the total metallicity distribution around the mode for the different luminosity samples.}
%\centering
\par
\begin{tabular}{cccccccccc}   
\hline
\hline
{}&\multicolumn{3}{c} {l-sample $a$}  &\multicolumn{3}{c}  {l-sample $b$} &  \multicolumn{3}{c}{ l-sample $c$}\\\cline{5-7}
\hline
Redshift&Mean&Mode&66$\%$-range&Mean&Mode&66$\%$-range&Mean&Mode&66$\%$-range\\\hline
$z_0$&9.02&9.04&8.94--9.11&&&\\\
$z_1$&8.99&9.04&8.95--9.12&9.00&9.03&8.92--9.10&8.97&9.03&8.90--9.17\\\
$z_2$&&&&8.99&9.01&8.92--9.08&8.97&9.03&8.94--9.12\\\
$z_3$&&&&&&&8.92&8.92&8.64--8.99\\\hline
\end{tabular}
\end{table}