\begin{table}%Ta2
\par
\caption{\label{coverage}Uncertainty tests done for the OSA 7.0 and PPDF spectral extraction 
methods. $\chi ^{2}$ is summed over all 500 shots, $\bar{\sigma}$ is an 
arithmetic mean of the standard deviation errors, $f_{1\sigma}$ is a fraction 
of shots covering the true count rate value inside the error limits and $f_{\rm s}$ 
is a similar fraction of shots computed for the shortest credible interval errors
for the PPDF method. Three rows at the bottom present the results of the same 
test made for the background assumed to be 10 times higher than the default one.}
\small%\centering
\par
\begin{tabular}{cccccccc}
\hline\hline
Energy range & \multicolumn{3}{c}{OSA 7.0} & \multicolumn{4}{c}{PPDF} \\
\multicolumn{1}{c}{[keV]} & $\chi^{2}$ & $\bar{\sigma}$ & $f_{1 \sigma}$ & 
$\chi^{2}$ & $\bar{\sigma}$ & $f_{1 \sigma}$ & $f_{\rm s}$ \\
\hline
 14.0--17.8   & 471 & 0.0114 & 0.69 & 425 & 0.0089 & 0.73 & 0.72 \\
 17.8--21.6   & 566 & 0.0087 & 0.65 & 537 & 0.0084 & 0.66 & 0.64 \\
 21.6--25.4   & 467 & 0.0086 & 0.67 & 443 & 0.0084 & 0.71 & 0.71 \\
 25.4--31.2   & 478 & 0.0090 & 0.68 & 503 & 0.0087 & 0.68 & 0.68 \\
 31.2--37.9   & 481 & 0.0081 & 0.72 & 459 & 0.0078 & 0.73 & 0.71 \\
 37.9--45.6   & 513 & 0.0080 & 0.67 & 569 & 0.0076 & 0.65 & 0.63 \\
 45.6--55.1   & 489 & 0.0094 & 0.70 & 486 & 0.0085 & 0.72 & 0.68 \\
 55.1--68.5   & 508 & 0.0130 & 0.69 & 443 & 0.0105 & 0.74 & 0.56 \\
 68.5--85.8   & 447 & 0.0112 & 0.71 & 344 & 0.0088 & 0.78 & 0.65 \\
 85.8--112.6  & 462 & 0.0109 & 0.71 & 285 & 0.0083 & 0.82 & 0.61 \\
 112.6--166.2 & 460 & 0.0125 & 0.70 & 459 & 0.0091 & 0.71 & 0.75 \\
\hline
 25.4--31.2   & 537 & 0.0284 & 0.71 & 348 & 0.0225 & 0.78 & 0.66 \\
 45.6--55.1   & 487 & 0.0299 & 0.67 & 435 & 0.0221 & 0.72 & 0.75 \\
 85.8--112.6  & 513 & 0.0344 & 0.65 & 367 & 0.0207 & 0.76 & 0.88 \\
\hline 
\end{tabular} 
\end{table}