\begin{table}[h]
\centering
\caption{Regression summary table}
\begin{tabular}{llrrrrrr}
\hline
\hline
\quad   &       &    M1 &       &        &    M2 &       &        \\
\quad   &       &     b &    ll &     ul &     b &    ll &     ul \\
\hline
low & age   & 0.958 & 0.893 &  1.026 &       &       &        \\
\quad   & lwt   & 0.986 & 0.973 &  0.999 & 0.985 & 0.972 &  0.997 \\
\quad   & smoke & 1.740 & 0.886 &  3.417 & 1.757 & 0.898 &  3.438 \\
\quad   & ptl   & 1.812 & 0.916 &  3.586 & 1.706 & 0.874 &  3.330 \\
\quad   & ht    & 6.502 & 1.679 & 25.176 & 6.716 & 1.751 & 25.756 \\
\quad   & ui    & 2.095 & 0.856 &  5.126 & 2.159 & 0.889 &  5.245 \\
\quad   & ftv   & 1.024 & 0.729 &  1.437 &       &       &        \\
\hline
\hline
\end{tabular}
\end{table}
