*
* Example from section 11.7, starting page 314.
*
open data fultonfish.dat
data(format=free,org=columns) 1 111 date lprice quan lquan mon tue wed thu stormy mixed rainy cold totr $
 diff change
*
* Reduced form equations
*
linreg lquan
# constant stormy mon tue wed thu
linreg lprice
# constant stormy mon tue wed thu
*
* This checks for whether the shift variables which would identify the supply
* equation are jointly significant.
*
exclude
# mon tue wed thu
*
instruments constant stormy mon tue wed thu
linreg(inst) lquan
# constant lprice mon tue wed thu