\begin{table}
\centering
\begin{tabular}[t]{lrrrrrr}
\toprule
\multicolumn{1}{c}{ } & \multicolumn{2}{c}{no\_no (N=18)} & \multicolumn{2}{c}{yes\_yes (N=14)} & \multicolumn{2}{c}{ } \\
\cmidrule(l{3pt}r{3pt}){2-3} \cmidrule(l{3pt}r{3pt}){4-5}
  & Mean & Std. Dev. & Mean & Std. Dev. & Diff. in Means & Std. Error\\
\midrule
mpg & 16.6 & 3.9 & 24.6 & 5.4 & 7.9 & 1.7\\
cyl & 7.4 & 1.1 & 4.6 & 0.9 & -2.9 & 0.4\\
disp & 307.1 & 106.8 & 132.5 & 56.9 & -174.7 & 29.4\\
hp & 189.7 & 60.3 & 91.4 & 24.4 & -98.4 & 15.6\\
drat & 3.4 & 0.5 & 3.9 & 0.5 & 0.5 & 0.2\\
wt & 3.7 & 0.9 & 2.6 & 0.7 & -1.1 & 0.3\\
qsec & 16.7 & 1.1 & 19.3 & 1.4 & 2.6 & 0.4\\
am & 0.3 & 0.5 & 0.5 & 0.5 & 0.2 & 0.2\\
gear & 3.6 & 0.9 & 3.9 & 0.5 & 0.3 & 0.2\\
carb & 3.6 & 1.5 & 1.8 & 1.1 & -1.8 & 0.5\\
\bottomrule
\end{tabular}
\end{table}
