clear
set obs 200
gen x=runiform()
gen y=runiform()

nl (y={{b3}*x^3+{b2}*x^2+{b1}*x+{b0})
predictnl py=predict(),ci(lb ub) l(95)
scatter py lb ub x

参见sungmoo版主的帖子，

https://bbs.pinggu.org/thread-626426-1-1.html