\begin{table}%t2
%\centering
\par
\caption{\label{table:no4} Cosmological density parameters, with uncertainties
computed at 1$\sigma$ confidence limit, obtained by a Monte Carlo procedure.} 
\begin{tabular}{l c c c c} 
\hline\hline\\[-3.2mm] 
Sample & $\Omega_{\rm m}$ & $\Omega_{\Lambda}$ & $\Omega_k$ & $\chi^2$ \\ 
\hline 
 UNION + GRB & $0.26 \pm 0.14$ & $0.73 \pm 0.14$ & $0.01 \pm 0.04$ & $1.032$ \\
 UNION + GRB corrected & $0.25 \pm 0.10$ & $0.74 \pm 0.135 $ & $0.01 \pm 0.035$ & $1.00027$ \\ 
\hline 
\end{tabular}
\end{table}