\begin{table}%t4
 \caption{\label{table:wblmiscor}Correlations between detectors 19 and 22.}
 %\centering
\small
 \begin{tabular}{cccc}
 \hline\hline
 $\tbase$ & $(a+b)/2$ & $(a-b)/2$ & Overlap\\
 \hline
 2.5 s   & 0.826 & --0.003 & 0.793 \\
 15 s    & 0.901 & 0.005  & 0.966 \\
 1 min   & 0.925 & --0.011 & 0.991 \\
 1 h     & 0.998 & --0.013 & 0.99986 \\
 \hline
 \end{tabular}
\end{table}