\begin{table}%t4
\caption{\label{tab4}Number of periodic variables in various mass intervals.}
\par
%\centering
\small
\begin{tabular}{c|ccc|ccc|c}
\hline \hline 
&\multicolumn{3}{|c|}{ONC-This Study} &\multicolumn{3}{c|}{ONC-Combined data (H2002 + This study)} & NGC 2264\\ 
\hline
Mass Bins &$R$ $<$ $R_{\rm cluster}$ & $R$~$>$ $R_{\rm cluster}$ & Total & $R$ $<$ $R_{\rm cluster}$ & $R$~$>$ $R_{\rm cluster}$ & Total& \\ 
$I_{0}$ $\leq$ 13.6 or $M$ $\geq$ 0.4~$M_{\odot}$ & 4 & 14 & 18 & 73 & 113 & 186 & 161\\
13.6 $<$ $I_{0}$ $\leq$ 16.3 or 0.4~$M_{\odot}$ $\leq$ $M$ $<$ 0.075~$M_{\odot}$& 150 & 195 & 345 & 183 & 239 & 422 & 222\\
$I_{0}$ $>$ 16.3 or $M$ $<$ 0.075 $M_{\odot}$ & 44 & 80 & 124 & 49 & 90 & 139 & 21\\
\hline
\end{tabular}
\end{table}