\begin{table}%t1
\caption{\label{trends}Trends.}\vspace*{-2mm}
%\centering
\par
\begin{tabular}{l c c}
\hline\hline\noalign{\smallskip}
\qir\ trend& Spear-    &Signifi-\\
           & man $\rho$&-cance\\
\hline
\multicolumn{3}{l}{Sample 1 (250-$\mu$m-selected galaxies with redshifts):}\\
 (5.02 $\pm$ 0.18)--(0.105 $\pm$ 0.008)~log~\l1.4 &$-0.48$&99.8\%\\
 (6.09 $\pm$ 0.33)--(0.092 $\pm$ 0.008)~log~\lir  &$-0.32$&95.6\%\\
 (2.61 $\pm$ 0.02)--(0.081 $\pm$ 0.007)~(1+$z$)    &$-0.33$&96.0\%\\
 (2.76 $\pm$ 0.03)--(0.008 $\pm$ 0.001)~\td\       &$-0.33$&96.1\%\\
\hline
\multicolumn{3}{l}{Sample 2 (radio-selected galaxies with redshifts):}\\
 (4.92 $\pm$ 0.21)--(0.101 $\pm$ 0.009)~log~\l1.4 &$-0.27$&99.9\%\\
 (2.74 $\pm$ 0.35)--(0.007 $\pm$ 0.009)~log~\lir  &$+0.07$&69.1\%\\
 (2.55 $\pm$ 0.02)--(0.047 $\pm$ 0.010)~(1+$z$)    &$-0.15$&96.6\%\\
 (2.60 $\pm$ 0.02)--(0.002 $\pm$ 0.001)~\td\       &$-0.16$&89.2\%\\
\hline
\end{tabular}
\vspace{-2.5mm}\end{table}