*
* Example 9.9 from page 314
*
open data rdchem.raw
data(format=free,org=columns) 1 32 rd sales profits rdintens profmarg salessq lsales lrd
*
linreg lrd
# constant lsales profmarg
*
linreg(smpl=(sales<30000)) lrd
# constant lsales profmarg