*
* Example 7.12 from page 244
*
open data crime1.raw
data(format=free,org=columns) 1 2725 narr86 nfarr86 nparr86 pcnv avgsen tottime ptime86 qemp86 inc86 durat black hispan born60 pcnvsq pt86sq inc86sq
*
set arr86 = narr86>0
linreg arr86
# constant pcnv avgsen tottime ptime86 qemp86
*
linreg arr86
# constant pcnv avgsen tottime ptime86 qemp86 black hispan