\begin{tabular}{*{3}{l}}
 \hline
                &\multicolumn{2}{c}{M1}   \\
                &Estimate &(S.E.) \\
 \hline
 \hline
  (Intercept)    &  4.997  &   (17.977) \\
  x1             &  0.324  &   (0.394) \\
  x2             & -0.058  &   (0.4) \\
  x1:x2          &  0.001  &   (0.007) \\
 \hline 
 N                &100      &       \\
 RMSE            &7.199        & \\
 $R^2$           &0.166        & \\
 adj $R^2$       &0.14        & \\
 \hline
 \hline
 
 \multicolumn{2}{l}{${*}  p \le 0.05$   }\\
 \end{tabular}