Table in IEEE paper format

Question

I'm trying to create the below table by using the below packages, but the format of it is not well organised especially the numbers as they need to be in the centre and the tabs. can someone please help to make the table more adjustable and look professional?

\documentclass[conference]{IEEEtran}
\IEEEoverridecommandlockouts
\usepackage{booktabs,tabulary,lipsum}
\usepackage{dcolumn,tipa}
\newcolumntype{d}{D{.}{.}{6.5}}
\usepackage{siunitx}
\usepackage[usestackEOL]{stackengine}
\usepackage{multirow}
\begin{document}
\begin{table}[ht]
\caption{Table ex.}
\label{tab1}
\centering
\renewcommand\footnoterule{\kern -1ex}
\renewcommand{\arraystretch}{1.3}
\begin{tabular}{\linewidth}{l{9}{d}}
\toprule \multirow{3}{}{Subjects}   &
\multicolumn{4}{c}{Numbers} & 
\multicolumn{4}{c}{Numbers}\
\cmidrule(r){2-5}\cmidrule(l){6-9}  &
\multicolumn{1}{c}{XYZ} & 
\multicolumn{1}{c}\addstackgap{\stackanchor{XYZ}{(Numbers)}} & 
\multicolumn{1}{c}{Numbers Tree} & 
\multicolumn{1}{c}{Numbers Tree} & 
\multicolumn{1}{c}{XYZ} & 
\multicolumn{1}{c}\addstackgap{\stackanchor{XYZ}{(Numbers)}} & 
\multicolumn{1}{c}{Numbers Tree} & 
\multicolumn{1}{c}{Numbers Tree} \\midrule
X1 & 0.5000 & 0.4888 & 0.0112 & 0.0001 & 0.8500 & 0.3540 & 0.2332 & 0.2367 \
X2 & 0.5000 & 0.4888 & 0.0112 & 0.0001 & 0.8500 & 0.3540 & 0.2332 & 0.2367 \
X3 & 0.5000 & 0.4888 & 0.0112 & 0.0001 & 0.8500 & 0.3540 & 0.2332 & 0.2367 \
X4 & 0.5000 & 0.4888 & 0.0112 & 0.0001 & 0.8500 & 0.3540 & 0.2332 & 0.2367 \
X5 & 0.5000 & 0.4888 & 0.0112 & 0.0001 & 0.8500 & 0.3540 & 0.2332 & 0.2367 \\bottomrule
\end{tabular*}
\end{table*}
\end{document}

And the result is this:

Answer 1

You should use the S columns of siunitx.

 \documentclass[conference]{IEEEtran}
 \IEEEoverridecommandlockouts
\usepackage{booktabs,tabulary,lipsum}
 \usepackage{dcolumn,tipa}
 \newcolumntype{d}{D{.}{.}{6.5}}
 \usepackage{siunitx}
 \usepackage[usestackEOL]{stackengine}
 \usepackage{multirow}
\begin{document}
\begin{table}[ht]
 \sisetup{
 table-number-alignment = center,
 table-figures-integer = 1,
 table-figures-decimal = 4
 }
 \caption{Table ex.}
 \label{tab1}
 \centering
 \renewcommand\footnoterule{\kern -1ex}
 \renewcommand{\arraystretch}{1.3}
 \begin{tabular}{l{8}{S}}
 \toprule \multirow{3}{*}{Subjects}   & 
 \multicolumn{4}{c}{Numbers} & 
 \multicolumn{4}{c}{Numbers}\
 \cmidrule(r){2-5}\cmidrule(l){6-9}  &
 \multicolumn{1}{c}{XYZ} & 
 \multicolumn{1}{c}\addstackgap{\stackanchor{XYZ}{(Numbers)}} & 
 \multicolumn{1}{c}{Numbers Tree} & 
 \multicolumn{1}{c}{Numbers Tree} & 
 \multicolumn{1}{c}{XYZ} & 
 \multicolumn{1}{c}\addstackgap{\stackanchor{XYZ}{(Numbers)}} & 
 \multicolumn{1}{c}{Numbers Tree} & 
 \multicolumn{1}{c}{Numbers Tree} \\midrule 
 X1 & 0.5000 & 0.4888 & 0.0112 & 0.0001 & 0.8500 & 0.3540 & 0.2332 & 0.2367 \
 X2 & 0.5000 & 0.4888 & 0.0112 & 0.0001 & 0.8500 & 0.3540 & 0.2332 & 0.2367 \ 
 X3 & 0.5000 & 0.4888 & 0.0112 & 0.0001 & 0.8500 & 0.3540 & 0.2332 & 0.2367 \ 
 X4 & 0.5000 & 0.4888 & 0.0112 & 0.0001 & 0.8500 & 0.3540 & 0.2332 & 0.2367 \ 
 X5 & 0.5000 & 0.4888 & 0.0112 & 0.0001 & 0.8500 & 0.3540 & 0.2332 & 0.2367 \\bottomrule
 \end{tabular}
\end{table*}
\end{document}

Answer 2

The main problem with your table is the unfortunate choice of 6.5 to format the 8 numerical columns; it should be 1.4 throughout. A second issue is that you employ a tabular* environment but give LaTeX no chance to achieve the desired overall width (here: \linewidth). Finally, there are only 8, not 9, columns of type d.

\documentclass[conference]{IEEEtran}
\IEEEoverridecommandlockouts
\usepackage{booktabs}
\usepackage{dcolumn,tipa}
\newcolumntype{d}[1]{D{.}{.}{#1}} % let the 'd' column type take an argument
%\usepackage{siunitx}             % not needed for this example
\usepackage[usestackEOL]{stackengine}
\usepackage{multirow}
\newcommand\mcc[1]{\multicolumn{1}{c}{#1}} % handy shortcut macro
\begin{document}
\begin{table}[ht]
\caption{Table example}
\label{tab1}
%%\centering % redundant
%%\renewcommand\footnoterule{\kern -1ex} % What is this instruction doing here??
\renewcommand{\arraystretch}{1.3}
\setlength\tabcolsep{0pt} % make LaTeX figure out the intercolumn separation
\begin{tabular}{\linewidth}{@{\extracolsep{\fill}} l {8}{d{1.4}} } % '1.4', not '6.5'
\toprule 
\multirow{3}{}{Subjects} & \multicolumn{4}{c}{Numbers} & \multicolumn{4}{c}{Numbers}\
\cmidrule{2-5} \cmidrule{6-9} &
\mcc{XYZ} & \mcc{\addstackgap{\stackanchor{XYZ}{(Numbers)}}} & 
\mcc{Numbers Tree} & \mcc{Numbers Tree} & 
\mcc{XYZ} & \mcc{\addstackgap{\stackanchor{XYZ}{(Numbers)}}} & 
\mcc{Numbers Tree} & \mcc{Numbers Tree} \
\midrule 
X1 & 0.5000 & 0.4888 & 0.0112 & 0.0001 & 0.8500 & 0.3540 & 0.2332 & 0.2367 \ 
X2 & 0.5000 & 0.4888 & 0.0112 & 0.0001 & 0.8500 & 0.3540 & 0.2332 & 0.2367 \ 
X3 & 0.5000 & 0.4888 & 0.0112 & 0.0001 & 0.8500 & 0.3540 & 0.2332 & 0.2367 \ 
X4 & 0.5000 & 0.4888 & 0.0112 & 0.0001 & 0.8500 & 0.3540 & 0.2332 & 0.2367 \ 
X5 & 0.5000 & 0.4888 & 0.0112 & 0.0001 & 0.8500 & 0.3540 & 0.2332 & 0.2367 \
\bottomrule
\end{tabular}
\end{table}
\end{document}