\begin{table}%t2
  \caption{\label{table2}Least-squares deviation, $\chi^2$, of the best fits to the relationships between the photospheric magnetic field and chromospheric emissions.}
\par
%\centerline
{\begin{tabular}{c|c|c|cr}
            \hline\hline&&&&\\[-2.5mm]
            Flux-flux & Linear$^{{\rm a}}$ & Power law$^{{\rm b}}$ with $b=0.6$ & \multicolumn{2}{c}{Power law$^{{\rm b}}$ } \\
            & $\chi^2$ & $\chi^2$ & $\chi^2$ & $b$ \\
            \hline
            $|B| - I_{\rm CaII ~K}$ & 11.97 & 9.17 & 8.44 & 0.31 $\pm$ 0.01   \\
            $|B| - I_{\rm 1600~\AA}$ & 11.53 & 10.64 & 10.47 & 0.36 $\pm$ 0.01  \\
            $|B| - I_{\rm 3.5~mm}$ & 161.68 & 132.78 & 111.06 & 0.20$^{{\rm c}}$ $\pm$ 0.01  \\
            \hline
    \end{tabular}}\smallskip
\par
$^{{\rm a}}$ See Eq.~(\ref{1});
$^{{\rm b}}$ see Eq.~(\ref{2});
$^{{\rm c}}$ calculated for $|B| \geq 4$~G. 
\end{table}