\begin{table}%T7
\caption{\label{kstest} Results of Kolmogorov-Smirnov Two-sample Test on
densities deduced from the four optical $N_{\rm e}$-diagnostic ratios. 
X~and~Y~denote the two density samples for the test, $D$ is the
Kolmogorv-Smirnov $D$~statistic of the samples, $P_0($$>$$|D|)$~gives the probability 
of exceeding $|D|$ under the Null Hypothesis and is equal to~1~minus confidence 
factor, $n$ is the size of the samples and $D(\alpha _{0.10})$ is the 
critical~$D$ value for a confidence factor of~0.10.}
%\centering
\par
\begin{tabular}{ccrccc}
\hline
\hline
 X & Y & $D$\hspace{4mm} & $P_0$($>$$|D|)$ & $n$ & $D(\alpha _{0.10})$ \\
\hline
[\ion{O}{ii}]& [\ion{S}{ii}] & 0.162 & 0.715 & 37 &0.284\\
\par
[\ion{O}{ii}]& [\ion{Cl}{iii}] &$-$0.139 & 0.878 &36 &0.288\\
\par
[\ion{O}{ii}]& [\ion{Ar}{iv}]  &0.245 & 0.106 &49 &0.246\\
\par
[\ion{S}{ii}]& [\ion{Ar}{iv}]  &$-$0.135 & 0.509 &62 & 0.200\\
\par
[\ion{S}{ii}]& [\ion{Cl}{iii}] &$-$0.113 & 0.824 &74 & 0.219\\
\par
[\ion{Ar}{iv}]& [\ion{Cl}{iii}] &0.152 & 0.498 &59&0.225 \\
 \hline
 \end{tabular}
\end{table}