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\begin{document}
\centering
\begin{tabular}{|c|c|c|c|c|} \hline
      & \multicolumn{2}{c|}{Q = 2} & \multicolumn{2}{c|}{Q = 3} \\ \hline
      & $z_{exp}$ & $z_{int}$ & $z_{exp}$ & $z_{int}$ \\ \hline
SW    & 0.30(1) & 0.295(5) & 0.56(1) & 0.561(5) \\
      & 0.29(1) & 0.208(5) & 0.56(1) & 0.516(7) \\
      & 0.30(1) & 0.255(5) & 0.56(1) & 0.537(7) \\ \hline
Wolff & 0.32(2) & 0.31(1) & 0.62(2) & 0.58(1) \\
      & 0.31(2) & 0.16(1) & 0.59(2) & 0.51(1) \\
      & 0.28(3) &  0 & 0.57(3) & 0.17(2) \\ \hline
LC    & 0.35(2) & 0.33(1) & 0.59(2) & 0.57(1) \\
      & 0.33(2) & 0.18(1) & 0.59(2) & 0.52(1) \\
      & 0.35(2) & 0.16(1) & 0.60(2) & 0.53(1) \\ \hline
AC    & - & - & 0.57(2) & 0.56(1) \\ 
      & - & - & 0.57(2) & 0.53(1) \\
      & - & - & 0.57(2) & 0.56(1) \\ \hline
\end{tabular}
\end{document}
