# problem C3.1
open bwght.gdt
corr cigs faminc
ols bwght const cigs
ci_lo = $coeff[2] - 2*$stderr[2]
ci_hi = $coeff[2] + 2*$stderr[2]
ols bwght const cigs faminc
ci_lo = $coeff[2] - 2*$stderr[2]
ci_hi = $coeff[2] + 2*$stderr[2]

# problem C3.2
open hprice1.gdt
# check the units
labels price
ols price const sqrft bdrms
printf "One more bedroom, sqrft constant: %g\n", $coeff[3]
printf "One more bedroom of 140 sqrft: %g\n", 
   $coeff[2]*140 + $coeff[3]
printf "Percent of variation explained: %g\n", 100*$rsq
matrix b = $coeff
pred_price = b[1] + b[2]*2438 + b[3]*4
resid = 300 - pred_price