*
*  Example 15.5
*  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 pension.raw
data(format=free,org=columns) 1 226 id pyears prftshr choice female married age educ $
  finc25 finc35 finc50 finc75 finc100 finc101 wealth89 black stckin89 irain89 pctstck
*
* Linear model.
*
linreg pctstck
# choice age educ female black married finc25 finc35 finc50 finc75 finc100 finc101 wealth89 prftshr constant
*
* Ordered probit. Drop the intercept.
*
ddv(type=ordered,dist=probit,cuts=cuts) pctstck
# choice age educ female black married finc25 finc35 finc50 finc75 finc100 finc101 wealth89 prftshr
*
compute x1=%dot(%beta,||1,60.0,13.5,0,0,0,0,0,0,1,0,0,200,1||)
compute x0=%dot(%beta,||0,60.0,13.5,0,0,0,0,0,0,1,0,0,200,1||)
compute p00 =%cdf(cuts(1)-x1)
compute p50 =%cdf(cuts(2)-x1)-p00
compute p100=1-p50-p00
disp "E(%stock|choice=1)" p00*0+p50*50+p100*100
compute p00 =%cdf(cuts(1)-x0)
compute p50 =%cdf(cuts(2)-x0)-p00
compute p100=1-p50-p00
disp "E(%stock|choice=0)" p00*0+p50*50+p100*100