*
*  Example 16.3
*  J. Wooldridge, Econometrics of Cross Section and Panel Data
*
*  Note: The sample data files include all required data transformations.
*        However, in many cases we show how these data transformations would
*        be created in RATS from the basic data, as this is something you will
*        need to know how to do in practice.
*
open data mroz.raw
data(format=free,org=columns) 1 753 inlf hours kidslt6 kidsge6 age educ wage repwage $
 hushrs husage huseduc huswage faminc mtr  motheduc fatheduc $
 unem city exper nwifeinc lwage expersq
*
set expersq = exper**2
*
* Estimate by OLS.
*
linreg hours
# nwifeinc educ exper expersq age kidslt6 kidsge6 constant
*
* Estimate by tobit. This is censored at zero on the low end.
*
ldv(censor=lower,lower=0.0) hours
# nwifeinc educ exper expersq age kidslt6 kidsge6 constant