Multivariate nonparametric methods in two-way balanced designs: performances and limitations in small samples

Investigations of multivariate population are pretty common in applied researches, and the two-way crossed factorial design is a common design used at the exploratory phase in industrial applications. When assumptions such as multivariate normality and covariance homogeneity are violated, the conventional wisdom is to resort to nonparametric tests for hypotheses testing. In this paper we compare the performances, and in particular the power, of some nonparametric and semi-parametric methods that have been developed in recent years. Specifically, we examined resampling methods and robust versions of classical multivariate analysis of variance (MANOVA) tests. In a simulation study, we generate data sets with different configurations of factor''s effect, number of replicates, number of response variables under null hypothesis, and number of response variables under alternative hypothesis. The objective is to elicit practical advice and guides to practitioners regarding the sensitivity of the tests in the various configurations, the tradeoff between power and type I error, the strategic impact of increasing number of response variables, and the favourable performance of one test when the alternative is sparse. A real case study from an industrial engineering experiment in thermoformed packaging production is used to compare and illustrate the application of the various methods.     

Fractional Moments and Maximum Entropy: Geometric Meaning

We consider the problem of recovering a probability density on a bounded or unbounded subset D of [0, ∞), from the knowledge of its sequence of fractional moments within a maximum entropy (MaxEnt) setup. Based upon entropy convergence results previously formulated, the fractional moments are selected so that the entropy of the MaxEnt approximation be minimum. A geometric interpretation of the reconstruction procedure is formulated as follows: the two moment curves generated by the unknown density and its MaxEnt approximation are interpolating in Hermite-Birkoff sense; that is, they are both interpolating and tangent at the selected nodes.     

Paradigmatic experiments: The Dictator Game

Recent experiments with the Dictator Game (and the ensuing discussions) have been affected by considerable confusion regarding the purpose of this design. A common complaint is that the design gives rise to fragile regularities and therefore is of little use for theory-testing. We take issue with this view, and instead argue that the Dictator Game is potentially a very useful tool for experimental game theory, if properly used. It is particularly useful for investigating social norms, but economists have failed to take advantage of the Dictator Game because they still lack an adequate theory of norms.     

Emergency Workers’ Quality of Life: The Protective Role of Sense of Community, Efficacy Beliefs and Coping Strategies

This study, involving a sample of 764 emergency workers, investigates dimensions of quality of life at work (Compassion fatigue, Burnout and Compassion satisfaction), and their relationships with Coping strategies and some psychosocial variables (Sense of Community, Collective Efficacy and Self-efficacy). Results indicate the usefulness of distinguishing between positive and negative indicators of emergency workers’ quality of life. Compassion satisfaction is positively correlated with efficacy beliefs, Sense of Community and the use of Active coping strategies. Burnout and Compassion fatigue are especially correlated with the use of dysfunctional coping strategies like distraction and self-criticism. Volunteer emergency workers enjoy a higher well being than full-time professional workers. Results and their implications for interventions aimed at increasing rescue workers’ quality of life by enhancing psychosocial competences are discussed.     

ENDOGENOUS NETWORKS IN RANDOM POPULATION GAMES

Population learning in dynamic economies traditionally has been studied in contexts where payoff landscapes are smooth. Here, dynamic population games take place over “rugged” landscapes, where agents are uncertain about payoffs from bilateral interactions. Notably, individual payoffs from playing a binary action against everyone else are uniformly distributed over [0, 1]. This random population game leads the population to adapt over time, with agents updating both actions and partners. Agents evaluate payoffs associated to networks thanks to simple statistics of the distributions of payoffs associated to all combinations of actions performed by agents out of the interaction set. Simulations show that: (1) allowing for endogenous networks implies higher average payoff compared to static networks; (2) the statistics used to evaluate payoffs affect convergence to steady-state; and (3) for statistics MIN or MAX, the likelihood of efficient population learning strongly depends on whether agents are change-averse or not in discriminating between options delivering the same expected payoff.     

About the “economic” origin of altruism

The principal aim of this paper is to present an evolutionary model based on a simple inequality system which shows how altruism can increase exchanges of goods and services, in order to study the conditions which can permit the emergence and prevalence of altruistic behaviors. We will show that given certain conditions, and even without considering group selection, kin selection or reciprocal altruism, altruists may have a greater probability of survival than egoists.     

LIQUIDITY AND INEFFICIENT INVESTMENT

We study consumer liquidity in a general equilibrium model where the friction is the nonpledgeability of future income. Liquidity helps to overcome the absence of a double coincidence of wants. Consumers over‐hoard liquidity and the resulting competitive equilibrium is constrained inefficient. Fiscal policy following a large negative shock can increase ex‐ante welfare. If the government cannot commit, the ex‐post optimal fiscal policy will be too small from an ex‐ante perspective. The model throws light on the holding of foreign reserves in international markets.