\begin{table}%T2
%\centering
\small
  \caption{Slopes of the linear fits ($b$) and their errors ($\Delta b$) of the
  different parameters in Fig.~\ref{panel} with the central velocity
  dispersion.  The left side of\protect the table shows the values for the LDEGs, while
  the right side of the table, the values for the HDEGs. The last two columns
  show the result of a $t$-test to verify if the slopes of both subsamples of
  galaxies are different. In particular, the last column shows the probability
  that the slopes\protect of HDEGs and LDEGs are different by chance.
  \label{mass-metallicity-fits}}
 \begin{tabular}{@{}l r r| r r r r@{}}
  \hline\hline
                  & \multicolumn{2}{c}{LDEG} & \multicolumn{2}{c}{HDEG}& &\\
  \hline
                  &\multicolumn{1}{c}{$b$}&\multicolumn{1}{c}{$\Delta
  b$}&\multicolumn{1}{c}{$b$}&\multicolumn{1}{c}{$\Delta b$} &
  \multicolumn{1}{c}{$t$}&\multicolumn{1}{c@{}}{$\alpha$}\\  
 $\rm [M/H]$ (CN$_2$) &$  0.00037$ & 0.00034       & 0.00138  & 0.00065    & 1.37&9\%\\
 $\rm [M/H]$ (Fe4383) &$ -0.00050$ & 0.00030       & 0.00085  & 0.00053    & 2.21&1\%\\
 $\rm [M/H]$ (Mgb)    &$  0.00113$ & 0.00031       & 0.00077  & 0.00042    & 0.69&24\%\\
 log (age)        &$  0.00177$ & 0.00033       & 0.00004  & 0.00064    & 2.41&1\%\\
  \hline
  \end{tabular}
\end{table}