*
* Example 4.10 from pp 155-156
*
open data meap93.raw
data(format=free,org=columns) 1 408 lnchprg enroll staff expend salary benefits droprate gradrate math10 $
 sci11 totcomp ltotcomp lexpend lenroll lstaff bensal lsalary
*
linreg lsalary
# constant bensal
test
# 2
# -1.0
linreg lsalary
# constant bensal lenroll lstaff
test
# 2
# -1.0
linreg lsalary
# constant bensal lenroll lstaff droprate gradrate
test
# 2
# -1.0