Merging data from multiple sources: pretest and shrinkage perspectives

In this article, we have developed asymptotic theory for the simultaneous estimation of the k means of arbitrary populations under the common mean hypothesis and further assuming that corresponding population variances are unknown and unequal. The unrestricted estimator, the Graybill-Deal-type restricted estimator, the preliminary test, and the Stein-type shrinkage estimators are suggested. A large sample test statistic is also proposed as a pretest for testing the common mean hypothesis. Under the sequence of local alternatives and squared error loss, we have compared the asymptotic properties of the estimators by means of asymptotic distributional quadratic bias and risk. Comprehensive Monte-Carlo simulation experiments were conducted to study the relative risk performance of the estimators with reference to the unrestricted estimator in finite samples. Two real-data examples are also furnished to illustrate the application of the suggested estimation strategies.     

An Attentional Application of Socioemotional Selectivity Theory in College Students

Socioemotional selectivity theory posits that emotions become increasingly salient as individuals approach endings. Recent findings have linked the theory with biases in information processing in the context of aging. However, these studies all confounded advancing age and the motivational impact of endings. This study represented an attempt to disentangle the effects of large age differences from those of endings on the processing of emotional information by investigating differences in attention to emotional stimuli between college seniors and college first‐years. Seniors represented a group approaching the social ending of graduation from college and first‐years served as a comparison group not facing an ending. Following recent findings in the literature on aging, it was hypothesized that seniors would selectively avoid negative images in an effort to better regulate their emotions in the face of this social ending. First‐years were found to spend a significantly larger portion of their time viewing sad faces than did seniors. Seniors also exhibited significantly higher levels of positive affect than did first‐years. These findings are discussed within the context of emotion regulation in the face of impending endings across the lifespan.     

Biased sampling with right censoring: A note on sun,Cui & Tiwari (2002)

Sun, Cui & Tiwari (2002) studied the asymptotic behaviour of certain goodness‐of‐fit tests in the presence of biased sampling and right censoring. The author illustrates that unfortunately, an assumption made by Sun, Cui and Tiwari on the independence between failure and censoring time fails to hold in many important applications, which limits the applicability of their results.     

Pitfalls in Drawing Policy Conclusions from Retrospective Survey Data: The Case of Advertising and Underage Smoking

Measuring the impact of potentially controllable factors on the willingness of youth to undertake health risks is important to informed public health policy decisions. Typically the only data linking these factors with risk-taking behavior are retrospective. This study demonstrates, by means of a recent example, that there can be serious pitfalls in using even longitudinal retrospective data to draw conclusions about causal relations between potentially controllable factors and risk-taking behavior.     

A new 'biased coin design' for the sequential allocation of two treatments

Summary.  Efron's biased coin design is a well-known randomization technique that helps to neutralize selection bias in sequential clinical trials for comparing treatments, while keeping the experiment fairly balanced. Extensions of the biased coin design have been proposed by several researchers who have focused mainly on the large sample properties of their designs. We modify Efron's procedure by introducing an adjustable biased coin design, which is more flexible than his. We compare it with other existing coin designs; in terms of balance and lack of predictability, its performance for small samples appears in many cases to be an improvement with respect to the other sequential randomized allocation procedures.     

Changes in Support From Confidants,Children, and Friends Following Widowhood

This paper examines the extent to which widowhood affects changes in (a) the availability of a confidant, (b) emotional support from children, and (c) emotional support from friends/relatives both 6 and 18 months after spousal loss. Analyses are based on data from the Changing Lives of Older Couples, a prospective study of 1,532 married individuals aged 65 and older. Compared to married persons, widowed persons are less likely to have a confidant, yet they receive greater support from children, friends, and relatives, controlling for support prior to widowhood. The findings suggest that, although close social relationships may remain stable in the course of normal aging, stressful events such as widowhood may bring forth both losses and gains in social support.     

代际研究中终生收入估算偏差问题探讨

在我国代际收入流动性问题研究中,微观数据分析常用父代40岁左右的单年收入替代其终生收入,由此导致代际收入弹性估计偏大问题。文章假定微观个体观测值服从对数正态分布并进行建模,对个体终生收入做出统计预测。模拟得到学历为硕士人群的工资年增长率是本科人群的1.06倍,收入达到峰值的时间则晚了约8年,对全部人群父代的终生收入用其40岁左右收入逼近的思路可依据父代教育水平进行再次细分。     

编辑无意识偏见及其控制

编辑偏见的存在有利有弊。编辑偏见有“有意识”与“无意识”之别。在编辑实践中,诱导编辑无意识偏见的发生因素主要有:认知懒惰或繁忙,非理性决策思维以及直觉信心等。编辑无意识偏见存在影响了编辑对稿件内容的客观评价,但因无意识编辑偏见具有较强的隐蔽性,消除比较困难,编辑必须通过无意识偏见发生前的“有意识”认知、严格落实“三审制”和利用大数据反馈等措施规避无意识偏见发生,以确保稿件价值选择的客观与公正。     

现代俄语口语中省略词的使用

口语是语言变化、发展的重要环节。口语中的诸多表现手段缺少不了省略词的使用，而省略词的使用恰恰迎合了现代各种语言发展、变化的一个共同趋势，即简化趋势。本文从四个方面对现代俄语口语中省略词的使用情况进行了详细阐述，揭示了其在使用过程中所产生的语义、语法、词汇、修辞等方面的特点。