\begin{table}%t4 \caption{\label{tab:correl}Results from statistical analysis of parameter pairs.} %\centerline {\begin{tabular}{ccccc} \hline \hline Param 1 & Param 2 & $N$ & $\tau_{\rm Kend}$ & $\rho_{\rm Spear}$ \\ \hline \rule{0pt}{2.6ex} $\log{\dot{M}_{\rm acc}}$ & Age & 16 & 0.05 & 0.08 \\ $B_z$ & \rule{0pt}{2.6ex} $\log{\dot{M}_{\rm acc}}$ & 16 & 0.68 & 0.57 \\ $\log{L_{\rm x}}$ & Age & 19 & 0.13 & 0.28 \\ $B_z$ & $\log{L_{\rm x}}$ & 19 & 0.09 & 0.07 \\ $B_z$ & $\log{(L_{\rm x}/L_{\rm bol})}$ & 19 & 0.14 & 0.19 \\ $B_z$ & $P_{\rm rot}$ & 20 & 0.50 & 0.42 \\ $B_z$ & Age & 27 & 0.03 & 0.05 \\ \hline \end{tabular}} \par \smallskip Notes: Parameter pairs are given in Cols.~1 and~2. $N$ is the number of data points, $\tau_{\rm Kend}$ and $\rho_{\rm Spear}$ denote the probability for no correlation according to Kendall's and Spearman's rank order correlation test, i.e.\ small numbers indicate that a correlation is present. \end{table}