Economic Efficiency of Wheat Producers: The Case of Debra Libanos District, Oromia, Ethiopia

Ethiopia has enormous potential for wheat production, yet it remains a net wheat importer. This paper aims to examine the efficiency of wheat production in Debra Libanos district, Ethiopia. Two stages sampling technique was used to randomly select 150 farmers for the study. A stochastic production frontier and two-limit Tobit estimator was utilized in the study. The study reveals that technical (78.5 %,), allocative (85.6%), and economic (66.7%) efficiencies. The yield gap was 5.13 quintal/ hectare showing a room to increase efficiencies. The study identified the determinants of wheat production efficiency in the area. Hence, to improve wheat production efficiencies strengthen extension services, improved technology utilization, and proper land ploughing. Besides, natural resource conservations that improve soil fertility should be the focus of the policymakers.

The (non) determinants of Olympic success

This paper empirically examines the determinants of Summer Olympic success during the period 1996-2016. By modifying the panel Tobit estimator using the Mundlak transform, the results find that population size and the host effect are the only statistically significant determinants of Olympic attainment. We also show that participating in front of a home crowd will stimulate athletic performance equally for each gender, but the impact of population differs between the sexes. These findings are confirmed using a hurdle estimator. This relaxes the assumption that the factors determining Olympic success are the same as those that influence the quantity of success.

MODELING CONSUMERS' PARTICIPATION IN GAMBLING MARKETS AND FREQUENCY OF GAMBLING

Survey data on participation in gambling typically contain many zeros. The presence of many zeros presents methodological problems for the analysis of participation in gambling markets and gambling expenditure. The most common techniques for handling zeros in gambling data have been the Tobit estimator and the Heckman selectivity estimator. Recent research indicates that hurdle models (Jones 1989, 2000) and the Cragg (1971) model, are better suited to analyze participation in gambling. We apply these models to gambling participation in Canada and find that the double hurdle model is preferred in two of the three forms of gambling examined.

Using limited dependent variable estimators for estimating percent decay

The data used for the estimation of percent decay are bounded by zero and 100. Because a value of 100% indicates that the tree is completely decayed, this value is not observable in nature. However, a value of zero percent is often observed over a wide range of the independent variables. The distribution of percent decay is a combination of a truncated continuous distribution for percent decay greater than zero and a discrete component for the zero percents. The use of ordinary least squares with this type of data results in biased and inconsistent estimates of the coefficients of a percent decay equation. An alternative is the tobit estimator (a combined regression and probit estimator based on a maximum likelihood equation), which results in consistent estimates of the coefficients if the error terms of the model are independent and identically distributed as the truncated normal distribution. A Monte Carlo simulation using data for three species with different proportions of zero percents was performed to compare the ordinary least squares and tobit estimators. As expected, the tobit estimator resulted in quite different estimates of the coefficients of the equations than did ordinary least squares. An unexpected result was that the estimated expected percent decay was slightly more biased for the tobit estimator than for the ordinary least squares estimator, even with a large number of zero percents in the data set. Possible explanations for the Monte Carlo simulation results and recommendations for fitting percent decay equations are given in the paper.

How Meaningful are Statements about the Desired Number of Additional Children? An Analysis of 1968 Pakistani Data

In this paper we present a methodology for studying the desired number of additional children. Our methodology involves a generalization of our earlier work. and an application of the estimator proposed by Heckman and the two-stage simultaneous Tobit estimator proposed by Nelson and Olson.