\begin{figure*}
\centering
{\small
\begin{tabular}{l|rrl|lrrrrr}  
 \textbf{} & \textbf{} & \textbf{} & \textbf{}&\multicolumn{6}{c}{\textbf{Historical Effort Data}}\\\cline{5-10} 
 \textbf{Dataset} & \textbf{Attributes} & \textbf{Number of cases} & \textbf{Content}&\textbf{Units}& \textbf{Min} & \textbf{Median} &\textbf{Mean} & \textbf{Max} & \textbf{Skewness}\\ \hline
  coc81 &17&63& NASA projects& months&6&98&683&11400& 4.4\\
  nasa93 &17&93& NASA projects&months&8&252&624&8211& 4.2\\ 
  desharnais &12&81& Canadian software projects&hours&546&3647&5046&23940& 2.0\\ 
maxwell & 26 & 62 & Finish banking software & months &6&5189&8223&63694&3.3\\
  isbsg &14&29& Banking projects of ISBSG&minutes&662&2355&5357&36046& 2.6\\\cline{3-3}
          \multicolumn{2}{c}{~}  & Total: 328& \multicolumn{7}{c}{~} 
\end{tabular}}
\caption{The 328 projects used in this study come from 5 data sets.
}\label{fig:data}
\end{figure*}
