Evidence of a new violation of the independence axiom

During the past 40 years there has been an accumulation of experimental evidence suggesting that most of the axioms of expected utility theory are liable to be systematically violated by substantial numbers of individuals. Much of this evidence has focused on failures of the independence axiom and has stimulated a number of alternative models that try to explain that evidence in various ways. This article presents a fresh experiment that looks at a different kind of violation—one that does not appear to be easily accommodated by several of the more prominent alternative models as they are currently formulated.The experimental work reported in this article was funded by Economic and Social Research Council Award No. B 00 23 2163.     

民进党当局的“台独外交”与东南亚

民进党当局出于地缘战略的考虑,在东南亚重点推行“台独外交”。一些东南亚国家由于历史、地理、经济、文化等诸多因素的考虑,采取的是一种在大陆和台湾之间搞平衡的实用主义政策,因而在台湾问题上不断突破对中国的承诺,使双边关系受到影响。东南亚国家应与中国联手遏制“台独”,这不仅有利于地区的和平、稳定与繁荣,也符合东南亚各国的根本利益。     

Testing independence based on Bernstein empirical copula and copula density

In this paper we provide three nonparametric tests of independence between continuous random variables based on the Bernstein copula distribution function and the Bernstein copula density function. The first test is constructed based on a Cramér-von Mises divergence-type functional based on the empirical Bernstein copula process. The two other tests are based on the Bernstein copula density and use Cramér-von Mises and Kullback–Leibler divergence-type functionals, respectively. Furthermore, we study the asymptotic null distribution of each of these test statistics. Finally, we consider a Monte Carlo experiment to investigate the performance of our tests. In particular we examine their size and power which we compare with those of the classical nonparametric tests that are based on the empirical distribution function.     

On fiducial generators

Fiducial inference has been gaining presence recently and it is the intention of the present article to look at the notion of fiducial generators; meaning procedures to simulate parameter values that in some sense correspond to simulations from some implicit fiducial distribution. It is well known that when the distribution has group structure, stemming from the natural pivotal associated, a fiducial may be obtained. It is in the non group distributions that there appears to be still room for finding a fiducial distribution. Recently some general procedures have been proposed for dealing with generalized fiducials, but these depend on certain choices for a structural equation or a fiducial equation, as in Hannig (2009 Hannig, J. (2009). On generalized fiducial inference. Stat. Sin. 19:491–544.[Web of Science ®] , [Google Scholar]) or Taraldsen and Lindqvist (2013 Taraldsen, G., Lindqvist, B.H. (2013). Fiducial theory and optimal inference. Ann. Stat. 41(1):323–341.[Crossref], [Web of Science ®] , [Google Scholar]), respectively. A brief presentation is made of an earlier approach to fiducial inference for multivariate parameters, as in Brillinger (1962 Brillinger, D.R. (1962). Examples bearing on the definition of fiducial probability with a bibliography. Ann. Math. Stat. 33(4):1349–1355.[Crossref] , [Google Scholar]), and the implied fiducial generator introduced in Engen and Lillegård (1997 Engen, S., Lillegård, M. (1997). Stochastic simulation conditioned on sufficient statistics. Biometrika 84(1):235–240.[Crossref], [Web of Science ®] , [Google Scholar]), trying to connect them. Three interesting non group distributions are seen; two of them, the truncated exponential and the two-parameter gamma, already reported in literature. A third non group distribution is analyzed; the inverse Gaussian, connecting the fiducial that results following Brillinger (1962 Brillinger, D.R. (1962). Examples bearing on the definition of fiducial probability with a bibliography. Ann. Math. Stat. 33(4):1349–1355.[Crossref] , [Google Scholar]), with a result pertaining confidence limits for the shape parameter in Hsieh (1990 Hsieh, H.K. (1990). Inferences on the coefficient of variation of an inverse-Gaussian distribution. Commun. Stat. - Theory Methods 19(5):1589–1605.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]). In the three cases, comparisons are made with the Bayesian posteriors that have been known to be close numerically. Some discussion is made on the issue of singularities of the fiducial density and its connection with densities that do not integrate to unity. As to the case of discrete observables, some comments are made for the Bernoulli distribution, only.     

Ignorability conditions for frequentist non parametric analysis of conditional distributions with incomplete data

Rubin (1976 Rubin, D.B. (1976). Inference and missing data. Biometrika 63(3):581–592.[Crossref], [Web of Science ®] , [Google Scholar]) derived general conditions under which inferences that ignore missing data are valid. These conditions are sufficient but not generally necessary, and therefore may be relaxed in some special cases. We consider here the case of frequentist estimation of a conditional cdf subject to missing outcomes. We partition a set of data into outcome, conditioning, and latent variables, all of which potentially affect the probability of a missing response. We describe sufficient conditions under which a complete-case estimate of the conditional cdf of the outcome given the conditioning variable is unbiased. We use simulations on a renal transplant data set (Dienemann et al.) to illustrate the implications of these results.     

Some novel results on pairwise quasi-asymptotical independence with applications to risk theory

In this article we obtain some novel results on pairwise quasi-asymptotically independent (pQAI) random variables. Concretely speaking, let X₁, …, X_n be n real-valued pQAI random variables, and W₁, …, W_n be another n non negative and arbitrarily dependent random variables, but independent of X₁, …, X_n. Under some mild conditions, we prove that W₁X₁, …, W_nX_n are still pQAI as well. Our result is in a general setting whether the primary random variables X₁, …, X_n are heavy-tailed or not. Finally, a special case of above result is applied to risk theory for investigating the finite-time ruin probability for a discrete-time risk model with a wide type of dependence structure.     

Robust test for independence in high dimensions

This article develops a new test based on Spearman’s rank correlation coefficients for total independence in high dimensions. The test is robust to the non normality and heavy tails of the data, which is a merit that is not shared by the existing tests in literature. Simulation results suggest that the new test performs well under several typical null and alternative hypotheses. Besides, we employ a real data set to illustrate the use of the new test.     

Parameter estimation for multivariate diffusion processes with the time inhomogeneously positive semidefinite diffusion matrix

Statistical inference for the diffusion coefficients of multivariate diffusion processes has been well established in recent years; however, it is not the case for the drift coefficients. Furthermore, most existing estimation methods for the drift coefficients are proposed under the assumption that the diffusion matrix is positive definite and time homogeneous. In this article, we put forward two estimation approaches for estimating the drift coefficients of the multivariate diffusion models with the time inhomogeneously positive semidefinite diffusion matrix. They are maximum likelihood estimation methods based on both the martingale representation theorem and conditional characteristic functions and the generalized method of moments based on conditional characteristic functions, respectively. Consistency and asymptotic normality of the generalized method of moments estimation are also proved in this article. Simulation results demonstrate that these methods work well.     

‘There’s a lot of places I’d like to go and things I’d like to do’: the daily living experiences of adults with mild to moderate intellectual disabilities during a time of personalised social care reform in the United Kingdom

Adult social care services in the United Kingdom have undergone a period of transformation over recent years, characterised by a drive towards personalised care. Concurrently, social care budgets have been significantly reduced. This study aimed to explore the daily living experiences of adults with mild/moderate intellectual disabilities, who are at risk of no longer meeting eligibility criteria for statutory support. Focus group discussions, which included both people with intellectual disabilities and support workers, were analysed thematically. Two broad themes are presented: independence and agency; and social capital and well-being. While some participants echoed ideas central to the personalisation narrative, a number of contextual barriers to achieving greater independence and agency were discussed. Moreover, greater independence was not a desired goal for all participants. The findings highlight the potential mismatch between personalised social care, as delivered within significant budget constraints, and the needs of adults with intellectual disabilities.     

Violence and political culture in Mozambique

This article is an attempt at developing a lens through which political culture in Mozambique can be analysed, described and interpreted. It is based on the notion of a political teleology that emerged out of the conditions within which the country fought for its independence. The paper argues that violence in a symbolic and physical form played a central role in the constitution of this political teleology by, on the one hand, allowing the liberation movement to produce an account of Mozambican history which both gave legitimacy to its own struggle while at the same time undermining alternative accounts and, on the other, set the scene for the implementation of a national project that came to be primarily concerned with the reproduction of the claim to power of the liberation movement. Forty years of independence in Mozambique offer an ideal time frame to attempt the construction of such a lens.