\begin{table}%T11
%%%%\centering


\par
\caption{Cross-check of membership derived for NGC~2451~A by
Platais et~al. (\cite{PKB}) and by our X-ray investigation.\label{platais} }
\begin{tabular}{lrr}
\hline\hline
Sample in field of & PSPC & HRI \\
\hline
in field-of-view:                & 54 & 14 \\
membership probability $>$50\%:  & 35 & 10 \\
B/A-type stars:                  & 10 &  4 \\
$\rightarrow$ late-type stars:   & 25 &  6 \\
non-members by our photometry:   &  3 &  0 \\
$\rightarrow$ comparison sample: & 22 &  6 \\
% \noalign{\smallskip}
\hline
% \noalign{\smallskip}
detected in X-rays:              & 13 &  5 \\
percentage:                      &59\%&83\%\\
\hline
% \noalign{\smallskip}
\end{tabular}
\end{table}