Risk aversion in n-person bargaining

Relations between risk properties of Pareto optimal n-person bargaining solutions are studied. The (weak) worse alternative property, risk sensitivity property, and risk profit opportunity property are considered, in particular relations between these properties, and between these properties and other properties such as independence of irrelevant alternatives and individual monotonicity. A distinction is made between bargaining games where all Pareto optimal outcomes are riskless, and bargaining games where Pareto optimal outcomes may represent the utilities of lotteries between riskless alternatives. In the first mentioned case, more general results can be obtained.     

A note on optimum linear feature extraction for gaussian populations with equal covariances and equal a priori probabilities

We consider the linear feature selection problem of obtaining a nonzero 1 × n matrix B which minimizes the probability of misclassification based on the Bayes decision rule applied to the random variable Y = BX, where X is a random n-vector arising from one of m Gaussian populations with equal covariances and equal apriori probabilities. It is shown that the optimal B satisfies a fixed point equation B = F(B) which can be solved by successive substitution.     

In Memoriam: George Zyskind 1929–1974

Improving the quality of presentations is an important goal of the American Statistical Association. This article summarizes information presented in workshops held at annual meetings to provide guidance for the presentation of statistical papers to general and technical audiences. Four key areas are emphasized in these workshops: (1) careful selection and organization of key themes and results to be presented; (b) construction and use of high-quality visual aids; (c) use of handouts for methodologic details; tables, graphs, and references; and (d) rehearsal, critique, and revision of oral delivery.     

The Fate Worse than Death and other Curiosities and Stupidities

The problem of finding confidence intervals for the success parameter of a binomial experiment has a long history, and a myriad of procedures have been developed. Most exploit the duality between hypothesis testing and confidence regions and are typically based on large sample approximations. We instead employ a direct approach that attempts to determine the optimal coverage probability function a binomial confidence procedure can have from the exact underlying binomial distributions, which in turn defines the associated procedure. We show that a graphical perspective provides much insight into the problem. Both procedures whose coverage never falls below the declared confidence level and those that achieve that level only approximately are analyzed. We introduce the Length/Coverage Optimal method, a variant of Sterne's procedure that minimizes average length while maximizing coverage among all length minimizing procedures, and show that it is superior in important ways to existing procedures.     

A Bayesian HMM with random effects and an unknown number of states for DNA copy number analysis

Hidden Markov models (HMMs) have been shown to be a flexible tool for modelling complex biological processes. However, choosing the number of hidden states remains an open question and the inclusion of random effects also deserves more research, as it is a recent addition to the fixed-effect HMM in many application fields. We present a Bayesian mixed HMM with an unknown number of hidden states and fixed covariates. The model is fitted using reversible-jump Markov chain Monte Carlo, avoiding the need to select the number of hidden states. We show through simulations that the estimations produced are more precise than those from a fixed-effect HMM and illustrate its practical application to the analysis of DNA copy number data, a field where HMMs are widely used.     

THE USE OF MODERATED REGRESSION IN JOB REDESIGN DECISIONS*

This paper describes the use of moderated regression in job redesign decisions. The procedures outlined are intended to augment the job redesign strategy described by Hackman and his colleagues. Different regression models based on a theory of job design are shown to lead to different job redesign decisions. Comparisons are also made between the moderated regression procedures and the more commonly used subgroups analysis.     

MODEL FORMULATION FOR FLEET SIZE ANALYSIS OF A UNIVERSITY MOTOR POOL

A GPSS/360 model was developed to investigate the behavior of a university's motor pool dispatch fleet. Time-series data were collected and frequency distributions were constructed for vehicle request patterns and trip-duration times. Regression analysis was performed to formulate trip mileage generators as functions of service time. Appropriate statistical goodness-of-fit tests were conducted to ascertain the extent of congruence between actual system behavior and expectations based on a number of theoretical distributions. Analysis of simulated response variables indicates that the model's internal structure reproduces reality to a high degree. Fifteen years of simulated experience were generated for six alternative fleet size configurations; results suggest that reductions in existing fleet capacity could be realized without effecting undue impairment in service levels.     

Longitudinal neural and behavioral trajectories of charity contributions across adolescence

This study examined the development of prosocial charity donations and neural activity in the ventral striatum when gaining rewards for self and for charity. Participants 10–22 years (95% European heritage) participated in three annual behavioral-fMRI waves (T1: n = 160, T2: n = 167, T3: n = 175). Behaviorally, donations to charity as measured with an economic Dictator Game increased with age. Perspective taking also increased with age. In contrast, self-gain and charity-gain enjoyment decreased with age. Ventral striatum activity was higher for rewards for self than for charity, but this difference decreased during adolescence. Latent growth curve models revealed that higher donations were associated with a smaller difference between ventral striatum activation for self and charity. These findings show longitudinal brain–donations associations in adolescence.     

Prognostic accuracy for predicting ordinal competing risk outcomes using ROC surfaces

Lifetime Data Analysis - Many medical conditions are marked by a sequence of events in association with continuous changes in biomarkers. Few works have evaluated the overall accuracy of a...