begin{tabular}{lcccccc} hline
& & Data1 & & & Data2 & \
VARIABLES & 1 & 2 & 3 & 4 & 5 & 6 \ hline
x1 & coef1 & coef2 & coef3 & coef4 & coef5 & coef6 \
first second & no & no & yes & no & no & yes \
third & & & & & & \
hline
end{tabular}