*
* Example 6.2 from page 192
*
open data hprice2.raw
data(format=free,org=columns) 1 506 price crime nox rooms dist radial proptax stratio lowstat $
  lprice lnox lproptax
*
set ldist = log(dist)
set roomsq = rooms**2
*
linreg lprice
# constant lnox ldist rooms roomsq stratio