\begin{figure*}
\centering
{\scriptsize  
\begin{tabular}{l|rrl|lrrrrr}  
 \textbf{} & \textbf{} & \textbf{} & \textbf{}&\multicolumn{6}{c}{\textbf{Historical Effort Data}}\\\cline{5-10} 
 \textbf{Dataset} & \textbf{Features} & \textbf{Size} & \textbf{Description}&\textbf{Units}& \textbf{Min} & \textbf{Median} &\textbf{Mean} & \textbf{Max} & \textbf{Skewness}\\ \hline
  cocomo81 &17&63& NASA projects& months&6&98&683&11400& 4.4\\
  \hspace{4 mm}cocomo81e &17&28& Cocomo81 embedded projects&months&9&354&1153&11400& 3.4\\ 
  \hspace{4 mm}cocomo81o &17&24& Cocomo81 organic projects&months&6&46&60&240& 1.7\\ 
  \hspace{4 mm}cocomo81s &17&11& Cocomo81 semi-detached projects&months&5.9&156&849.65&6400&2.64 \\ 
  nasa93 &17&93& NASA projects&months&8&252&624&8211& 4.2\\ 
  \hspace{4 mm}nasa93\_center\_1 &17 &12 & Nasa93 projects from center 1&months&24 &66 &139.92 &360 &0.86 \\ 
  \hspace{4 mm}nasa93\_center\_2 &17&37& Nasa93 projects from center 2&months&8&82&223&1350& 2.4\\ 
  \hspace{4 mm}nasa93\_center\_5
   &17&40& Nasa93 projects from center 5&months&72&571&1011&8211& 3.4\\ 
  desharnais &12&81& Canadian software projects&hours&546&3647&5046&23940& 2.0\\ 
  \hspace{4 mm}desharnaisL1 &11 &46 & Projects in Desharnais that are developed with Language1 & hours &805 &4035.5 &5738.9 &23940 &2.09 \\ 
  \hspace{4 mm}desharnaisL2 &11 &25 & Projects in Desharnais that are developed with Language2 & hours &1155 &3472 &5116.7 &14973 &1.16 \\ 
  \hspace{4 mm}desharnaisL3 &11 &10 & Projects in Desharnais that are developed with Language3 & hours &546 &1123.5 &1684.5 &5880 &1.86 \\ 
  sdr &22&24& Turkish software projects& months&2&12&32&342& 3.9\\ 
  albrecht &7&24& Projects from IBM&months&1&12&22&105& 2.2\\ 
  finnish &8 &38 &Software projects developed in Finland  &hours &460 &5430 &7678.3 &26670 &0.95 \\
  kemerer &7 &15 &Large business applications  &months &23.2 &130.3 &219.24 &1107.3 &2.76 \\
  maxwell &27 &62 &Projects from  commercial banks in Finland  &hours&583 &5189.5&8223.2&63694&3.26 \\
  miyazaki94 &8 &48 &Japanese software projects developed in COBOL  &months &5.6 &38.1 &87.47 &1586 &6.06 \\
  telecom &3 &18 &Maintenance projects for telecom companies  &months &23.54 &222.53 &284.33 &1115.5 &1.78 \\
  china &18 &499 &Projects from Chines software companies  &hours &26 &1829 &3921 &54620 &3.92 \\\cline{3-3}
          \multicolumn{2}{c}{~}  & Total: 1198& \multicolumn{7}{c}{~} 
\end{tabular}}
\caption{The 1198 projects used in this study come from 20 data sets.
Indentation in column one denotes a dataset that is a subset of another dataset.
 For notes
on this datasets, see the appendix.}\label{fig:datasets}
\end{figure*}