/usr/share/gretl/scripts/ps6-7.inp is in gretl-common 2016a-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 | # PS6.7 for Example 6.5
open data6-4
logs WAGE
square EDUC EXPER AGE
ols l_WAGE const EDUC EXPER AGE sq_EDUC sq_EXPER sq_AGE
omit AGE
omit sq_AGE
omit sq_EXPER
omit EDUC
|