Firstly, a binary regression model was used to examine the factors determining the participation of farmers in the use of guti urea technology. Secondly, treatment effect was assessed by the Heckman's two-stage
Further, it is important to note that unlike the situation in the analysis of two stage least squares procedures, the portion of the residual that arises from the use of an estimated value of hi in place of the actual value of hi is not orthogonal to the X1 data vector. This portion ...