\begin{table}%t3
\caption{Correlation coefficients ($r$), number of stars used to define the upper
 envelope ($N$), parameters of the linear, exponential and power law  weighted fits
 to the upper data envelope of the $L_{\rm X}$/$L_{\rm bol}$--$P$ and $L_{\rm
 X}$/$L_{\rm bol}$--$R_{\rm 0}$ relations and reduced chi-squares ($\chi^2_{\rm
 \nu}$).}
\label{tabcoeff-lx}
%\centering
$$
\begin{tabular}{@{\hspace{.1cm}}l@{\hspace{.1cm}}r@{\hspace{.1cm}}|l@{\hspace{.1
cm}}|l@{\hspace{.2cm}}l@{\hspace{.2cm}}l@{\hspace{.1cm}}|l@{\hspace{.1cm}}l@{\hspace{.1cm}}l@{\hspace{.1cm}}|l@{\hspace{.2cm}}l@{\hspace{.2cm}}l@{\hspace{.1cm}}
}
\hline
\hline
Sp.   &  $r$      &  $N$  &     $a$\hskip 1cm   $\sigma$     &          $b$\hskip 1cm 
 $\sigma$     &   $\chi^2_{\nu}$ &   $\log$($a$)\hskip 0.5cm $\sigma$ & $b$\hskip
 1cm $\sigma$& $\chi^2_{\nu}$ & $\log$($a$)\hskip 0.5cm $\sigma$ & $b$\hskip 1cm
 $\sigma$& $\chi^2_{\nu}$\\
\hline
\multicolumn{12}{c}{}\\
\multicolumn{3}{c}{}  & \multicolumn{3}{c}{$L_{\rm X}$/$L_{\rm bol}$ = $a + bP$} &
 \multicolumn{3}{c}{$\log$($L_{\rm X}$/$L_{\rm bol}$) = $\log(a)+bP$}    &
 \multicolumn{3}{c}{$\log$($L_{\rm X}$/$L_{\rm bol}$) = $\log(a)+b\log_{\rm 10}P$}\\ 
\multicolumn{12}{c}{}\\
F & $-$0.43 &  13&
     0.0006     0.0284  &    $-$0.0001     0.0082   &    6.50  &
     $-$3.1793     0.0283  &   $-$0.2572     0.0082    & 32.6  &
   $-$3.2861     0.0251  &    $-$1.8118     0.0553   &    24.4   \\
G &  $-$0.66 & 36&
   0.0008     0.0149  &   $-$0.0001     0.0048   &    11.1&
 $-$2.8821     0.0149   &  $-$0.2036     0.0048  &    19.2   &
   $-$2.8530     0.0154  &   $-$1.7031     0.0408   &    19.8  \\
K & $-$0.67 & 63&
 0.0007      0.0084  &    $-$0.0001     0.0007  &     14.1&
  $-$2.9075       0.0084  &    $-$0.1302     0.0007  &   15.0     &
 $-$2.5001      0.0107  &    $-$1.8202     0.0100   &     20.0  \\
M&  $-$0.56&   26&
  0.0009     0.0029   &   $-$0.0001     0.0014    &    8.1  &
    $-$2.9236     0.0029   &   $-$0.0684     0.0014  &    19.2    &
  $-$2.8143     0.0055   &   $-$0.8576     0.0191    &    25.12  \\
\hline
\multicolumn{12}{c}{}\\
\multicolumn{3}{c}{}  & \multicolumn{3}{c}{$L_{\rm X}$/$L_{\rm bol}$ = $a + bNR$}
 & \multicolumn{3}{c}{$\log$($L_{\rm X}$/$L_{\rm bol}$) = $\log(a)+bNR$}    &
 \multicolumn{3}{c}{$\log$($L_{\rm X}$/$L_{\rm bol}$) = $\log(a)+b\log NR$}\\ 
\multicolumn{12}{c}{}\\
F & $-$0.46 &   13&
   0.0006      0.0281   &  $-$0.0008     0.0538    &   9.0&
     $-$3.1716      0.0281  &   $-$1.7846     0.0538  &   40.3    &
   $-$4.8510      0.0307  &   $-$1.8758     0.0519    &    21.6\\
G & $-$0.70 &  36&
  0.0007      0.0157   &   $-$0.0012      0.0642  &   11.4&
     $-$2.8954     0.0157 &     $-$2.5622      0.0642 &   13.5   &
  $-$4.7399      0.0350   &   $-$1.7402      0.0439  &    14.2 \\
K &  $-$0.69  & 63  &
  0.0006      0.0080    &  $-$0.0009      0.0125   &   12.6  &
    $-$3.0463      0.0080  &   $-$2.1011      0.0125  &    10.2  &
   $-$4.6869     0.0021   &   $-$1.5073      0.0090   &    13.6 \\
M & $-$0.57 &  26&
  0.0010      0.0030    &  $-$0.0014      0.0379   &   8.1&
    $-$2.9206      0.0030  &    $-$1.8149      0.0379 &    18.9    &
  $-$4.0394      0.0219   &   $-$0.8686      0.0193  &    25.7 \\
\hline
\end{tabular}
$$
\end{table}