Estimation of technical efficiency of black cumin (Nigella sativa L.) farming in northwest Ethiopia: a stochastic frontier approach

Journal of Economic Structures

The Official Journal of the Pan-Pacific Association of Input-Output Studies (PAPAIOS)

Table 4 OLS and ML estimate of production frontier for black cumin producers

Variables	Parameters	Ordinary least square estimates		Maximum likelihood estimates
Variables	Parameters	Coefficient	Std. err	Coefficient	Std. err
Constant	\(\beta_{0}\)	0.547*	0.324	0.683**	0.345
Lnseed	\(\beta_{1}\)	0.190**	0.080	0.332***	0.097
LnNPS	\(\beta_{2}\)	0.032	0.026	− 0.043	0.031
Lnland	\(\beta_{3}\)	0.240**	0.097	0.227**	0.103
LnChemical	\(\beta_{4}\)	0.251***	0.047	0.185***	0.049
LnOxen	\(\beta_{5}\)	0.049	0.114	0.052	0.112
LnLabor	\(\beta_{6}\)	0.159*	0.085	0.202**	0.080
Sigma-squared \(\left( {\sigma^{2} } \right)\)				0.211***	0.036
Gamma \(\left( \gamma \right)\)				0.849***	0.076
Return to scale				0.946
Log likelihood function		− 127.582		− 91.247
Total sample size		188		188