set verbose off
open eurowages.gdt

# baseline model
ols wage const educ exper male
square exper

# with square of exper added
ols wage const educ exper sq_exper male

# now use the log of wage as dependent variable
logs wage
ols l_wage const educ exper sq_exper male -w
matrix b = $coeff
matrix se = $stderr

# max. experience effect? set derivative to zero
maxeffect = -b[3]/(2*b[4])
printf "exper effect maximized at %g\n", maxeffect

# "male" effect
printf "Males are expected to earn about %g percent more\n",
  100 * b[5]
lo = b[5] - 2*se[5]
hi = b[5] + 2*se[5]
printf "95 percent CI: %g to %g\n", lo, hi

# "take a look at" the exper variable
summary exper --simple