Rezensionen

Ohne Zusammenfassung     

A logic system for the choice of risk levels in hypothesis testing

We have examined current, traditional practice of establishing risk levels, favoring use of small α and implicitly accepting correspondingly larger β errors. There are both loses and gains associated with this approach. In particular, small a minimizes the probability of erroneously rejecting H_o, but it also increases the chances that a new model, representing a real improvement, may be discarded. There is no overwhelming logic that one type of error is always more important than the other, since relative costs vary with the conditions surrounding the research investigation.     

A Laboratory Science Approach to Teaching in the Agricultural Economics Curriculum

We argue that economic laboratory experiments can facilitate active learning of theory in the agricultural economics curriculum by placing students in decision-making roles. Three types of experimental protocols are described, along with a discussion of the costs and benefits of experiments. The Double Auction Experiment provides a platform for demonstrating concepts of equilibrium, price discovery, externalities, excess supply, surplus, and speculation. The Monopoly Experiment is a platform for demonstrating concepts of advance production, inventory carryover, monopoly pricing, and search strategies. The Oligopoly Experiment is a platform for demonstrating concepts of thin markets, coordination, and imperfectly competitive equilibria.     

Short note: Stein's two-stage procedure for the intra-class model

In his nice paper (Mykhopadhyay, 1982) as well as in his significant monograph (Mykhopadhyay & Solanky, 1994) N. Mykhopadhyay considers the following application of STEIN's two-stage procedure: Suppose that (X ₁,..., X_n ) ^T , n = 1, 2,..., is n-dimensional normal with mean vector µ = µ l and dispersion matrix Σ _n =σ ²(ρ_ij ) with ρ_ij = 1, ρ_ij = ρ ^*, i ≠ j = 1,..., n where (µ, Σ, ρ) ∈ ? × ?⁺ × (-1, 0); this is called the intra-class model. For given d > 0 and α ∈ (0, 1) one wants to construct a (sequential) confidence interval I for µ having width 2d and confidence coefficient at least (1 - α). It is claimed that where N is determined, according to Stein's two-stage procedure (Stein, 1945), as where m ? 2 is the first stage sample size and denotes the sample variance, fulfills this aim.     

Credibility of government policy: Lessons for economies in transition

Reforms have to be credible in order to fully reveal the intended positive effects. This important lesson for economies in transition is illustrated by recent experiences in developing countries. The following article discusses several possible ways of enhancing credibility. This paper reports research undertaken in the project “The Role of Stabilization, Liberalization and Privatization in the Process of Transformation in Central and Eastern Europe”. Financial support provided by the Volkswagen Foundation is gratefully acknowledged. I thank Peter Nunnenkamp for helpful comments on an earlier draft.