Lester V. Manderscheid

Advanced econometric methods

1 Introduction.- 2 Review of Ordinary Least Squares and Generalized Least Squares.- 3 Point Estimation and Tests of Hypotheses in Small Samples.- 4 Large Sample Point Estimation and Tests of Hypotheses.- 5 Stochastic Regressors.- 6 Use of Prior Information.- 7 Preliminary Test and Stein-Rule Estimators.- 8 Feasible Generalized Least Squares Estimation.- 9 Heteroscedasticity.- 10 Autocorrelation.- 11 Lagged Dependent Variables and Autcorrelation.- 12 Unobservable Variables.- 13 Multicollinearity.- 14 Varying Coefficient Models.- 15 Models That Combine Time-Series and Cross-Section Data.- 16 The Analysis of Models with Qualitative or Censored Dependent Variables.- 17 Distributed Lags.- 18 Uncertainty in Model Specification and Selection.- 19 Introduction to Simultaneous Equations Models.- 20 Identification.- 21 Limited Information Estimation.- 22 Full Information Estimation.- 23 Reduced Form Estimation and Prediction in Simultaneous Equations Models.- 24 Properties of Dynamic Simultaneous Equations Models.- 25 Special Topics in Simultaneous Equations.- Appendix Estimation and Inference in Nonlinear Statistical Models.- A.1 Nonlinear Optimization.- A.1.1 Method of Steepest Ascent.- A.1.2 The Method of Newton.- A.1.3 Method of Quadratic Hill Climbing.- A.1.4 Numerical Differentiation.- A.2 Maximum Likelihood Estimation.- A.2.1 Use of the Method of Newton.- A.2.2 Method of Scoring.- A.2.3 The Method of Berndt, Hall, Hall, and Hausman.- A.2.4 Asymptotic Tests Based on the Maximum Likelihood Method.- A.2.4a The Wald Test.- A.2.4b The Lagrange-Multiplier Test.- A.2.4c The Likelihood Ratio Test Statistic.- A.2.4d Concluding Remarks.- A.3 Nonlinear Regression.- A.4 Summary and Guide to Further Readings.- A.5 References.

U.S. Import Demand for Green Coffee by Variety

Total United States imports of green coffees were divided into three principal components: milds, brazils, and robustas. The aim was to clarify the demand relationships among the major coffee varieties traded internationally and the factors influencing coffee prices by variety. A nine-equation model of the U. S. coffee market was constructed, consisting of import-demand, export-supply, and stock-demand functions describing the structural mechanisms underlying the market for each of the three coffee varieties. Estimates of structural parameters were obtained by different estimation methods, but only three-stage least-squares results are reported in this article. Parameter estimates suggest that milds (the premium coffee variety) are normal economic goods, whereas brazils and robustas are inferior goods with respect to the U. S. economy. Income flexibility estimates at the mean were 0.39, −0.89, and −1.82, respectively, for milds, brazils, and robustas. Estimated price flexibilities at the mean were, for the three coffee varieties in the same order, −0.18, −0.21, and −0.36. These figures suggest that demand for individual coffee varieties is reasonably price-elastic.

Some Observations on Interpreting Measured Demand Elasticities

The purpose of this paper is to relate some of the problems encountered in measuring price and income elasticities to the interpretation of these measurements. Since this material is familiar to the demand analyst, the paper is addressed to users of elasticities. It draws heavily on empirical literature in demand analysis to indicate the relationship of empirical procedures to interpretation of results. The discussion should aid users of elasticities in reconciling some of the diverse estimates of a particular elasticity and be of assistance in choosing a relevant elasticity for specific decisionmaking problems.

Present Status of Quantitative Techniques in Undergraduate Agricultural Economics Programs

Undergraduate training in quantitative analysis has undergone considerable change in recent years. Attempts have been made to raise the level of mathematical and statistical sophistication of agricultural economics undergraduate majors. However, in most undergraduate programs computer technology and econometric modeling are still relatively underutilized teaching and learning devices.

Better Teaching—Some Curricular Aspects

B ETTER teaching can be approached in a variety of ways including creation of a better environment for learning, more careful attention to class preparation, examination techniques, changed motivations on the part of students and others. All are important, but I want to focus on another dimension-the dimension of what is to be learned. In addition to all the other attributes of good teaching, it is clear that one of the teachers major roles is guiding the studies of students under his direction. Before a curriculum can be evaluated, we need to assess our student audience and define our educational goals. I assume that our educational goals involve developing the student into an educated man and into an applied problem solver with special emphasis on the practical social science problems of individuals or groups either in agriculture or in rural areas.