Accent on Teaching Materials

This department includes the two sections New Developments in Statistical Computing and Statistical Computing Software Reviews; suitable contents for each of these sections are described under the respective section heading. Articles submitted for the department, outside the two sections, should not be highly technical and should be relevant to the teaching or practice of statistical computing.

An unbiased estimator of e is used to motivate a simple simulation exercise that requires only observations from the distribution uniform on (0, 1). Antithetic variables are introduced and applied to the simulation problem to give a second unbiased estimator of e with reduced variance.     

Adolescent girls’ race/ethnic status, identities, and drive for thinness

Using data from 7272 adolescent US girls, we explore how girls’ race/ethnic group status affects their bodyweight, perceptions of overweight, and weight control practices. We hypothesize that a girl’s race/ethnic status influences her basic identity which in turn prompts her to adopt or reject a “drive for thinness.” After controlling for family and peer support, school engagement, family SES, maturation, and family structure, we find that girls’ race/ethnic status influences their susceptibility to the thinness ideals of mainstream culture. African American girls weigh more than Asian, Hispanic, or White girls, but at any given weight they perceive themselves as overweight and attempt to control their weight less. Asian American and White girls invest most in thinness dynamics. Some evidence also suggests girls from lower SES families are less driven to be thin. Our results affirm the utility of viewing material bodies as “situations” that are experienced and interpreted in accord with identity group relations and dynamics.     

Convergence Rate of Wavelet Expansions of Gaussian Random Processes

This article characterizes uniform convergence rate for general classes of wavelet expansions of stationary Gaussian random processes. The convergence in probability is considered.     

Uniform asymptotics for ruin probability of a two-dimensional dependent renewal risk model

ABSTRACT

In this paper we consider the tail behavior of a two-dimensional dependent renewal risk model with two dependent classes of insurance business, in which the claim sizes are governed by a common renewal counting process, and their inter-arrival times are dependent, identically distributed. For the case that the claim size distribution belongs to the intersection of long-tailed distribution class and dominant variation class, we obtain an asymptotic formula, which holds uniformly for all time in an infinite interval. Moreover, we point out that the formula still holds uniformly for all time in an infinite interval for widely dependent random variables (r.v.s) under some conditions.     

The crisis of 'identity' in high modernity

The concept of 'identity' is central to much contemporary sociology, reflecting a crisis that manifests itself in two ways. Firstly, there is a view that identity is both vital and problematic in this period of high modernity. Secondly, while this awareness is reflected in sociology, its accounts of identity are inconsistent, under-theorized and incapable of bearing the analytical load required. As a result, there is an inherent contradiction between a valuing of identity as so fundamental as to be crucial to personal well-being, and a theorization of 'identity' that sees it as something constructed, fluid, multiple, impermanent and fragmentary. The contemporary crisis of identity thus expresses itself as both a crisis of society, and a crisis of theory. This paper explores the diverse ways in which 'identity' is deployed before turning to case-studies of its use by Anthony Giddens and Manuel Castells. This strategy demonstrates the widespread and diverse concern with identity before exploring how problematic it has become, even in the work of two of the world's leading sociologists.     

Voice and Identity in a Bicultural/Bilingual Environment

Researchers have noted that with the onset of adolescence, girls' voices become muted and school achievement drops. Girls learn that the expression of strong feelings leads to distance from others, and that full use of their bodies and minds cause others discomfort. Self-esteem suffers and girls become at risk for destructive behaviors. Most studies have been done with middle class Caucasian girls. Those few studies done with young girls of color speak of girls on the margin who seem to resist losing their voices and their self-esteem. This article describes a study involving 5th–8th grade girls participating in an Advisory group program at a grammar school in a predominantly Mexican community of a large city. Group sessions were taped and analyzed for common themes including voice and self-esteem. Focus was directed to the influence of the bicultural/bilingual environment in analysis of group content. Implications for practice are included.     

Point estimation of lower quantiles based on two-sampling scheme

ABSTRACT

Consider a two-sampling scheme in which an initial sample is first taken from the underlying population and then by assuming a suitable restriction on this sample, some more data points are observed as a new restricted sample. This sampling scheme is used to do inference about the lower quantiles of the underlying distribution. The results are compared with those of simple random sampling in view of mean squared error and Pitman’s measure of closeness criteria for exponential and uniform distributions. It will be shown that the proposed sampling scheme would improve the performance of the point estimators of the lower quantiles of the population.     

随机序列的可积性

本文给出了广鞅差随机序列一致可积性条件，及其一个非一致可积鞅的广鞅差序列的典型例子，说明右闭下鞅不一定一致可积。     

On Bayesian estimators in multistage binomial designs

A new class of Bayesian estimators for a proportion in multistage binomial designs is considered. Priors belong to the beta-J distribution family, which is derived from the Fisher information associated with the design. The transposition of the beta parameters of the Haldane and the uniform priors in fixed binomial experiments into the beta-J distribution yields bias-corrected versions of these priors in multistage designs. We show that the estimator of the posterior mean based on the corrected Haldane prior and the estimator of the posterior mode based on the corrected uniform prior have good frequentist properties. An easy-to-use approximation of the estimator of the posterior mode is provided. The new Bayesian estimators are compared to Whitehead's and the uniformly minimum variance estimators through several multistage designs. Last, the bias of the estimator of the posterior mode is derived for a particular case.     

SOCIAL MOVEMENT NETWORKS VIRTUAL AND REAL

This paper discusses the impact of 'computer mediated communication' (or CMC) on political activism and social movements. CMC may be expected to affect collective action by improving the effectiveness of communication and facilitating collective identity and solidarity. However, the heterogeneity of social movements undermines generic arguments and their relationship to CMC. Accordingly, the potential consequences of CMC on three different types of political organizations are discussed: organizations mobilizing mainly participatory resources, organizations focusing on professional resources, and transnational networks. The potential to build 'virtual [social movement] communities' seems highest among sympathizers of movement organizations who act professionally on behalf of causes with vast resonance among the public opinion and low radical potential. All in all, the most distinctive contribution of CMC to social movements still seems to be instrumental rather than symbolic. Existing bonds and solidarities are likely to generate more effective mobilization attempts than was the case before the diffusion of CMC; it is more disputable though as to whether CMC may create brand new social ties where there were none.