Rapid advances in modelling research have created new challenges and opportunities for statisticians. Statistical inference in observational studies and many other emerging fields have motivated ...statisticians worldwide to develop cutting-edge methods and analytical strategies. The aim of this reprint is to showcase the applications and methodological research in all fields of computational statistics. This reprint will provide a forum for computer scientists, mathematicians, and statisticians working in a variety of areas in statistics, including biometrics, econometrics, data analysis, graphics, and simulation.
Population aging was one of the most distinctive events of the 20th century and will remain important throughout the 21st century. Initially, a phenomenon of more developed countries, the process has ...recently become apparent in much of the developing world as well. The shift in age structure associated with population aging has a profound impact on a broad range of economic, political, and social conditions. This report provides an overview of the world population aging process, focusing on five relevant public policy issues. In dealing with the issues, the report notes the course of the aging process, which has not been the same in all countries. There has been considerable variation in timing, levels, and patterns. The report's assessment of the general trends is disaggregated into development regions and major geographic areas whenever possible. There are five chapters: (1) "Demographic Determinants of Population Ageing" examines the worldwide decline in fertility and mortality that underlies population aging; (2) "The Magnitude and Speed of Population Ageing" explores regional differences in the progression of the aging process through analysis of the percentages and growth rates of the older groups of the population; (3) "The Changing Balance between Age Groups" highlights, from various perspectives, the changes in the relative size of the older and younger groups of the population; (4) "A Demographic Profile of the Older Population" draws attention to two important features of the aging process: the progressive aging of the older population itself and its feminization; and (5) "The Socio-Economic Characteristics of the Older Population" focuses on two dimensions that can greatly affect the well-being of older individuals: labor force participation and literacy. (Contains 40 references and 36 figures. Annex tables include: (1) Definition of the Indicators of Population Ageing"; (2) "Classification of Major Areas and Regions"; and (3) "Profiles of Ageing.") (BT)
The statistical characteristics of wind speed data recorded at nine buoys, located in Ionian and Aegean Sea (Eastern Mediterranean) are analyzed in this paper, in order to present a more accurate ...method for estimation of wind speed characteristics, according to the suitability of the probability distribution functions (pdf). This article has focussed on wind regimes that present nearly zero percentages of null wind speeds. The selected distributions for examination are the typical two-parameter Weibull wind speed distribution (W-pdf) and the two-component mixture Weibull distribution (WW-pdf), involving five parameters (two shape parameters, two scale parameters, and one proportionality parameter).
Suitable software, based on the maximum likelihood method, is used in order to estimate the aforementioned two-parameters of the typical W-pdf and the five parameters of the mixed WW-pdf. The suitability of the aforementioned distributions is judged from the coefficient of determination (
R
2) and the fit standard error (
RMSE) tests, which had been carried out between each one of the theoretical distributions and the corresponding experimental cumulative frequencies of the nine selected sites. From these tests it is clear that, in most cases (six experimental stations - having either unimodal or bimodal frequency distributions), mixed-Weibull distribution provides the highest degree of fit. In the other three cases, the mixing weight
p of the two-component mixed Weibull density function equals to zero (
p
=
0), so the mixed-Weibull distribution is been transformed to the typical Simple-Weibull distribution.
Hence, the general conclusion is that the aforementioned mixture of two Weibull distributions is more suitable for the description of such wind conditions and could offer less relative errors in determining the annual mean wind power density.
A fairly general procedure is studied to perturb a multivariate density satisfying a weak form of multivariate symmetry, and to generate a whole set of non-symmetric densities. The approach is ...sufficiently general to encompass some recent proposals in the literature, variously related to the skew normal distribution. The special case of skew elliptical densities is examined in detail, establishing connections with existing similar work. The final part of the paper specializes further to a form of multivariate skew t-density. Likelihood inference for this distribution is examined, and it is illustrated with numerical examples.
Civilized nations popularly assume that “primitive” societies are poor, ill, and malnourished and that progress through civilization automatically implies improved health. In this provocative book, ...Mark Nathan Cohen challenges this belief. Using findings from epidemiology, anthropology, and archaeology, Cohen provides fascinating evidence about the actual effects of civilization on health, suggesting that some aspects of “progress” create as many health problems as they prevent or cure.
This book will help practitioners in various helping career fields to design and implement effective cross-cultural interventions, and to provide optimum assistance to clients from world cultures, ...through an understanding of both indigenous and foreign cultures. This revised edition includes additional information about peoples near and far, and more than one-third of this edition is new. The chapters in this book sharpen the focus on relationships between ethnicity, social class, and therapeutic practice. In so doing the authors explore answers to four interrelated questions: What do people want from their human services system? What do they actually get from them? How effective are various systems? When and under what conditions will people change to another system? The authors have carefully analyzed the data that have significant academic reliability and validity by drawing information from scholars in several fields of study that capture the essence of intrapersonal, interpersonal, intergroup, and organizational interactions. By identifying indigenous and foreign social values and practices, features of social systems that cause them to be similar and different from each other are discerned. Using two different approaches, the authors compare and contrast modern and traditional helping practices, which will help to identify and suggest alternative transcultural helping strategies when appropriate. It is written primarily for students interested in pursuing careers as professional helpers, but it should also be of value to experienced practitioners and reference librarians. The major foci are on multidisciplinary concepts pertaining to a potpourri of cultural groups, and special attention is paid to activities that will assist the reader to get in touch with his or her own beliefs about cross-cultural and cross-national helping.
This detailed introduction to distribution theory uses no measure theory, making it suitable for students in statistics and econometrics as well as for researchers who use statistical methods. Good ...backgrounds in calculus and linear algebra are important and a course in elementary mathematical analysis is useful, but not required. An appendix gives a detailed summary of the mathematical definitions and results that are used in the book. Topics covered range from the basic distribution and density functions, expectation, conditioning, characteristic functions, cumulants, convergence in distribution and the central limit theorem to more advanced concepts such as exchangeability, models with a group structure, asymptotic approximations to integrals, orthogonal polynomials and saddlepoint approximations. The emphasis is on topics useful in understanding statistical methodology; thus, parametric statistical models and the distribution theory associated with the normal distribution are covered comprehensively.
When a p×p$$ p\times p $$ real positive definite matrix S$$ S $$ follows a Wishart or, more generally, a matrix‐variate gamma distribution with shape parameter α$$ \alpha $$ and positive definite ...scale parameter matrix B$$ B $$, one can represent S$$ S $$ as XX′$$ X{X}^{\prime } $$ for some matrix X$$ X $$ of dimension p×q$$ p\times q $$. When p>q$$ p>q $$, S$$ S $$ has a singular distribution whose properties can be studied via the density function of X$$ X $$. It will be shown that when X$$ X $$ follows a matrix‐variate extended Gaussian distribution, the density function of the resulting singular gamma distribution can be obtained by making use of successive transformations and their associated Jacobians. The singular Wishart distribution will then be obtained as a particular case. The marginal and conditional density functions resulting from an arbitrary partitioning of X$$ X $$ will be considered as well. The same technique will also be applied to the derivation of the density functions of real and complex singular type‐1 and type‐2 beta‐distributed matrices. It so happens that the proposed approach, which is based on manipulations involving the wedge products of certain differential elements, generally proves more efficient than the intricate procedures that have hitherto been employed in the literature.
Résumé
Lorsqu'une matrice réelle définie positive S$$ S $$ (p×p)$$ \left(p\times p\right) $$ suit une loi de Wishart ou, plus généralement, une distribution gamma de paramètre de forme α$$ \alpha $$ et de paramètre d'échelle une matrice définie positive B$$ B $$, il est possible de représenter S$$ S $$ sous forme XX′$$ X{X}^{\prime } $$ où X$$ X $$ est une matrice de dimension p×q$$ p\times q $$. Lorsque p>q$$ p>q $$, S$$ S $$ a une distribution singulière dont les propriétés peuvent être étudiées via la fonction de densité de X$$ X $$. Les auteurs de cet article montrent que lorsque X$$ X $$ suit une distribution gaussienne étendue à variable matricielle, la fonction de densité de la distribution gamma singulière résultante peut être obtenue en utilisant des transformations successives et leurs Jacobiens associés. La distribution de Wishart singulière en découle comme un cas particulier. Le cas de fonctions de densité marginale et conditionnelle résultant d'un partitionnement arbitraire de X$$ X $$ a également été traité. La même technique a été utilisée pour déterminer les fonctions de densité de matrices singulières réelles et complexes de lois beta de type 1 et de type 2. Ainsi l'approche proposée, basée sur des manipulations mettant en jeu les produits extérieurs de certains éléments différentiels, s'avère généralement plus efficace que les procédures complexes utilisées jusqu'à présent dans la littérature.
