Parameter estimation of Lindley step stress model with independent competing risk under type 1 censoring

Abstract

In literature, Lindley distribution is considered as an alternative to exponential distribution to fit lifetime data. In the present work, a Lindley step-stress model with independent causes of failure is proposed. An algorithm to generate random samples from the proposed model under type 1 censoring scheme is developed. Point and interval estimation of the model parameters is carried out using maximum likelihood method and percentile bootstrap approach. To understand the effectiveness of the resulting estimates, numerical illustration is provided based on simulated and real-life data sets.     

Finie mixures of canonical fundamenal skew $$$$-disribuions

This paper introduces a finite mixture of canonical fundamental skew \(t\) (CFUST) distributions for a model-based approach to clustering where the clusters are asymmetric and possibly long-tailed (in: Lee and McLachlan, arXiv:1401.8182 [statME], 2014b). The family of CFUST distributions includes the restricted multivariate skew \(t\) and unrestricted multivariate skew \(t\) distributions as special cases. In recent years, a few versions of the multivariate skew \(t\) (MST) mixture model have been put forward, together with various EM-type algorithms for parameter estimation. These formulations adopted either a restricted or unrestricted characterization for their MST densities. In this paper, we examine a natural generalization of these developments, employing the CFUST distribution as the parametric family for the component distributions, and point out that the restricted and unrestricted characterizations can be unified under this general formulation. We show that an exact implementation of the EM algorithm can be achieved for the CFUST distribution and mixtures of this distribution, and present some new analytical results for a conditional expectation involved in the E-step.     

Trustworthiness in evaluation practice: an emphasis on the relational

As canons for trustworthiness developed explicitly in the discourse of qualitative inquiry, the emphasis was on procedural matters rather than fundamentally relational ones. A nod was made to the relational in such strategies as “member checks” but the issues of how the evaluator actually relates to participants and to the larger communities of practice and discourse—matters subsumed under moral principles and ethical standards—were often marginalized. This chapter posits that the first consideration in designing and conducting rigorous evaluation inquiry, and in critiquing the results of any research, should be the study's trustworthiness. Judging a study's trustworthiness, however, should focus on much more than procedural matters; it should also rely on moral principles and ethical standards which specifically address how we relate to an evaluation's participants. Central to these considerations are cross-cultural sensibilities about the nuanced meanings associated with any principles and standards. The chapter provides a theoretical framework for this position and offers two illustrative examples in the form of dialogues.     

Characteristics of the female athlete triad in collegiate cross-country runners

The Female Athlete Triad is a life-threatening syndrome defined by disordered eating, amenorrhea, and osteoporosis. OBJECTIVE AND PARTICIPANTS: The author's purpose in this study was to examine female cross-country runners' (N=300) calcium consumption, along with the prevalence of 2 components of the triad: disordered eating and menstrual dysfunction. METHODS: The author used measures including the Orientation to Exercise Questionnaire, Calcium Rapid Assessment Method, and questions related to height, weight, exercise time, perceptions of eating disorders, and menstrual status. Previous or current eating disorders were reported by 19.4% of the women, 23.0% had irregular menstrual cycles, and 29.1% had inadequate calcium intake. RESULTS: Those athletes perceiving a previous/current eating disorder scored higher on the Orientation to Exercise questionnaire than did those who did not perceive such. CONCLUSION: The author recommends educational efforts for the prevention of components of the Female Athlete Triad.     

Pearls and pitfalls in evaluating a Student Assistance Program: a five-year case study

This article presents data from a five-year evaluation-research case study of a large urban schools district's internal Student Assistance Program (SAP). The district employed specially trained and licensed school-based counselors to implement an internal SAP expanded to include tertiary prevention, and modeled after an employee assistance program established for adults. From the population of more than 10,000 students who received some type of program assistance for at-risk behaviors, a stratified random sample of 2,238 cases, over a five year period, were reviewed. Results indicate a statistically significant decline (p < .05) in students' drug use and a significant improvement in internal locus of control occurred each year. While not statistically significant, the average number of student discipline referrals was less than the year prior to program admission; however, there was no significant change in academic performance. A significant correlation between students' drug use and the amount of time in program, the type of assistance received, and the student's custody status was also found.     

Reflecting on the Past: A Content Analysis of Family Therapy Research from 2000‐2015

In this content analysis, researchers examine articles published from 2000 to 2015 in three family therapy journals, yielding a total of 948 empirical articles. The purpose is to provide an overview of the research being published, assess who is publishing, and investigate the current state of clinical effectiveness research in marriage and family therapy (MFT). Most first authors were affiliated with MFT programs and primarily included diversity and couples in their research. There was a significant increase of research on clinical process—though the number of clinical outcome studies held steady. There were no significant changes with regard to research funding. Implications support the use of innovative research methods to provide evidence of clinical effectiveness.     

Doing business or leading care work? Intersections of gender,ethnicity and profession in home care entrepreneurship in Sweden

This article critically explores assumptions underpinning Swedish elder care policies that the introduction of market practices in publicly funded eldercare services advances women's entrepreneurship. We argue that gendered privileges and disadvantages are being recreated on tax‐funded home care markets; furthermore, gendered inequalities intersect with ethnicity and profession in the management of small‐scale care companies' dealings with authorities governing home care services and standards for home care work. However, we find that the salience of categories depends on the context in which they emerge. While gender and profession are dominant in management, gender and ethnicity influence interactions with authorities. Only in standards for home care work do all categories simultaneously shape the business approaches of care entrepreneurs. Our analysis, based on data on size and growth of home care companies and interviews with small‐scale care entrepreneurs, suggests that regulations and practices privilege big companies and care entrepreneurs who echo the white, masculine gendering of entrepreneurship as ‘doing business' and disadvantage small‐scale entrepreneurs focusing on leading care work to produce quality care.     

预期寿命增长、年龄结构改变与我国国民储蓄率

人口年龄结构趋于老龄化和人均预期寿命逐步增长是目前我国人口发展的两个典型特征,而年龄阶段不同,个人的收入、消费与储蓄行为也不同。基于生命周期理论,在选定相关分析指标的基础上,文章使用我国省际平衡面板数据,实证分析了我国人口预期寿命增长和年龄结构改变对国民储蓄率的影响。分析结论表明,人口预期寿命增长提高了我国国民储蓄率;不考虑时间效应时,幼年人口负担比提高会减少国民储蓄率,而老年人口负担比提高会增加国民储蓄率;在考虑时间效应时,幼年人口负担比提高会增加国民储蓄率,而老年人口负担比提高会减少国民储蓄率。对此,文章给出了合理的解释。通过使用多种估计方法,我们发现所得到的结论是基本稳健的。