Approximating discrete multivariate distributions prom known moments

To approximate the joint distribution of the two-colony stepping-stone model, a finite mixture approach is proposed for constructing discrete multi-variate distributions. This approach generahzes the classic method of linear combinations of independent variables. The stepping-stone model is approximated through matching known moments. Numerical examples from entomology are given. Comparisons are made with the work by Wehrly et al (1993).     

Moments and generating functions for the absortion distribution and its negative binomial analogue

The moments of the absorption are difficult to obtain. The generating functions are basic hypergeometric functions. This paper shows how to define two shift operators that allow elementary arguments to be used to develop recursions for the expected values of general functions. The exact moments of the distribution follow. The generating function for the negative binomial analogue gives the moments directly.     

Reliability Characteristics of the Maxwell Distribution: A Bayes Estimation Study

ABSTRACT

This article presents maximum likelihood, Bayes, and empirical Bayes estimators of the truncated first moment and hazard function of the Maxwell distribution. A comparison of the relative efficiency of these three estimators is performed via a Monte Carlo simulation study.     

基于Monte Carlo模拟的STAR模型样本矩性质研究

采用Monte Carlo模拟方法对STAR模型样本矩的统计特性进行研究。分析结果表明:STAR模型的样本均值、样本方差、样本偏度及样本峰度都渐近服从正态分布;即使STAR模型的数据生成过程中不含有常数项,其总体均值可能也不是0,这与线性ARMA模型有显著区别;即使STAR模型数据生成过程中的误差项服从正态分布,数据仍有可能是有偏分布。     

Parameter measures of skewness

Several different measures of skewness are commonly used in place of γ₁, the third central moment divided by the cube of the standard deviation. The numerical values of these measures are compared in this paper for members of the gamma, lognormal or Weibull family of distributions and shown to vary considerably in most cases even when skewness and kurtosis are moderate.     

The beta generalized gamma distribution

For the first time, a new five-parameter distribution, called the beta generalized gamma distribution, is introduced and studied. It contains at least 25 special sub-models such as the beta gamma, beta Weibull, beta exponential, generalized gamma (GG), Weibull and gamma distributions and thus could be a better model for analysing positive skewed data. The new density function can be expressed as a linear combination of GG densities. We derive explicit expressions for moments, generating function and other statistical measures. The elements of the expected information matrix are provided. The usefulness of the new model is illustrated by means of a real data set.     

Understanding perceptions of substance use education in social work: an analysis of survey responses from MSW program leaders

ABSTRACT

This article details the findings of a series of analyses regarding how the institutional leaders of Master of Social Work Programs (MSW) in the United States form their perceptions on the role and implementation of substance use concepts in social work education. Five statistical tests were performed on data collected from a 2017 substance use education (SUE) survey of MSW program leaders, and the analyses were used to explore how program leaders form their perceptions on: the importance of SUE to social work, the need for regulatory measures for SUE in social work, the SUE needs of individual MSW programs, the implementation of substance use course content, and graduating students’ substance use intervention capacities. Significant findings from the analyses showed that: the amount of foundational course emphasis on clinical SUE within individual programs is a significant predictor of program leader perceptions on students’ clinical substance use intervention capacities; different categories of substance use intervention preparedness have interconnected effects among domains of preparedness; and perceptions on the importance of SUE to social work have a significant impact on program leaders’ opinions regarding regulatory measures for SUE in social work.     

What is this moment we are caught in?

Our response to the question ‘What is this moment we are caught in?' is articulated through our collaborative reading of Berlant's (2011) Cruel Optimism (Durham, NC: Duke University Press). Cruel optimism, Berlant suggests, is a desire for something that undermines its own potentiality. As queer academics we expose the cruelty of our desires to live a good academic life, and we do so from our different positions as postdoctoral fellow, tenured academic and PhD candidate. In labouring to consolidate relationships and practices that hold the promise of our own sustainability, we give accounts of the material and affective work we perform to constitute what Berlant calls an intimate public, a collective space of mediation that functions as a key tactic to manage our academic life. These accounts take the form of three vignettes, each inflected by the specificities of our different positions and histories of becoming academics. We use Berlant as a point of departure to both interrogate practices of self‐management and find possibilities for a collective response to the moments in which we find ourselves caught.     

Unequally Adrift: How Social Class and College Context Shape Students’ Mentorship Experiences

Faculty mentorship is a highly advantageous yet under-explored form of social capital which can grant access to co-curriculars (e.g., research assistantships), ensure strong letters of recommendation, and more. It is also typically informal and dependent on student initiative, requiring that students be skilled at engaging educational authority figures. Privileged students are most likely to have such skills as part of their dominant cultural capital, making faculty mentorship a site of social reproduction. To explore variations in this process, I compare two institution types: a small, teaching/undergraduate-focused regional university and a large, research-intensive flagship. In interviews with 68 working- and upper-middle-class students, I find that college context mediates the relationship of class background and faculty mentorship. Upper-middle-class students fostered advantageous faculty relationships at both universities, but working-class students diverged: at the flagship, they rarely approached professors in search of mentorship, while those at the regional university described close, beneficial connections with professors. I discuss working-class students’ dissimilar experiences in terms of each university’s structural and cultural characteristics (organizational habitus), particularly their institutional focus and size. I argue that through their particular organizational features, colleges can both reproduce and reduce inequalities, challenging the determinacy of precollege socialization in education.     

构建民办高校学生党建微博平台的思考

微博作为新媒体领域的一个重要平台，已经渗透到高校学生学习、生活的各个方面，其教育载体的属性已然显现。然而，目前民办高校学生党建微博平台的建设尚处于起步阶段。民办高校应充分认识构建学生党建微博平台的必要性，探索其可行性路径，思考其深层次问题，不断提高学生党建平台建设的现代化水平。