An extended Birnbaum–Saunders distribution: Theory,estimation, and applications

Abstract

Birnbaum and Saunders (1969a Birnbaum, Z.W., Saunders, S.C. (1969a). A new family of life distributions. J. Appl. Probab. 6:319–327.[Crossref], [Web of Science ®] , [Google Scholar]) pioneered a lifetime model which is commonly used in reliability studies. Based on this distribution, a new model called the gamma Birnbaum–Saunders distribution is proposed for describing fatigue life data. Several properties of the new distribution including explicit expressions for the ordinary and incomplete moments, generating and quantile functions, mean deviations, density function of the order statistics, and their moments are derived. We discuss the method of maximum likelihood and a Bayesian approach to estimate the model parameters. The superiority of the new model is illustrated by means of three failure real data sets. We also propose a new extended regression model based on the logarithm of the new distribution. The last model can be very useful to the analysis of real data and provide more realistic fits than other special regression models.     

Gaussian Markov random field spatial models in GAMLSS

This paper describes the modelling and fitting of Gaussian Markov random field spatial components within a Generalized AdditiveModel for Location, Scale and Shape (GAMLSS) model. This allows modelling of any or all the parameters of the distribution for the response variable using explanatory variables and spatial effects. The response variable distribution is allowed to be a non-exponential family distribution. A new package developed in R to achieve this is presented. We use Gaussian Markov random fields to model the spatial effect in Munich rent data and explore some features and characteristics of the data. The potential of using spatial analysis within GAMLSS is discussed. We argue that the flexibility of parametric distributions, ability to model all the parameters of the distribution and diagnostic tools of GAMLSS provide an ideal environment for modelling spatial features of data.     

A Dyadic Analysis of the Associations Between Cumulative Childhood Trauma and Psychological Intimate Partner Violence: The Mediating Roles of Negative Urgency and Communication Patterns

Prior research has suggested associations between cumulative childhood trauma (CCT), negative urgency, communication patterns, and psychological intimate partner violence (P-IPV), but no study has examined these links using a dyadic approach. This study examined the sequential mediation of negative urgency and communication patterns in the link uniting CCT and P-IPV in a sample of 501 heterosexual couples. Results suggest that more CCT events are associated with higher levels of negative urgency, which in turn are associated with a higher tendency to endorse a demand/withdraw and/or demand/demand communication pattern, and to perpetrate P-IPV. Findings support the need to assess CCT, emotional self-control, dyadic and communication patterns, and P-IPV perpetration and victimization in couples seeking help in order to select interventions that will take into account the individual and dyadic nature of P-IPV.     

Rising Age at Marriage and Fertility in Southern and Eastern Africa

This paper examines the trends in marriage and fertility in nine countries of southern and eastern Africa using DHS data. First, some background about the age at marriage, age at first birth and the proportion of premarital first births is shown. Next, the total fertility is decomposed into its pre- and post-marital parts. Then, pre- and post-marital fertility are examined in more detail. Finally, the effect of rising age at marriage on the fertility declines is measured. It is estimated that around one sixth to one third of the fertility declines are due to rising age at marriage.     

An Evaluation of Working on What Works (WOWW): A Solution-Focused Intervention for Schools

Working on What Works (WOWW) is a manualized, 10-week classroom intervention based on solution-focused brief therapy. This study evaluates WOWW using a randomized experimental, posttest-only design. The study included 30 fourth and fifth grade classrooms, containing 30 teachers and 413 students. Results indicate no significant differences between WOWW and control groups for student internalizing and externalizing behaviors, student–teacher relationships, student academic performance, or teacher sense of efficacy. However, students in the WOWW group had significantly fewer days absent from school compared with the control group. Additionally, teachers' ratings on WOWW classrooms' performance improved significantly more than teachers' ratings on the control classrooms. Results from this study show that WOWW is a feasible intervention for therapists to use in schools and can be implemented across classrooms in both public and private schools. WOWW has potential to improve student attendance and classroom performance, both of which are important areas of concern for schools.     

Short notices

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Charles Carlton, The Court of Orphans (1974), 145 (Leicester University Press, Leicester, £3.50).

Hans Christian Johansen, Belolkningsudvikling og familiestruktur i det 18. árhuadrede (1975). 211 (Odense University Press, Odense, Denmark, D.kv. 60+VAT). (Population and family structure in eighteenth‐century Denmark)

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Marcus Cunliffe, The Age of Expansion 1848–1917 (1974), 336 (Weidenfeld and Nicolson, £4.95).

Pamela and Harold Silver, The Education of the Poor. The History of a National School, 1824–1974 (1974), z+197 (Routledge and Kegan Paul, £3.95).     

Determinants of Long-Term Unions: Who Survives the “Seven Year Itch”?

Most studies of union formation focus on short-term probabilities of marrying, cohabiting, or divorcing in the next year. In this study, we take a long-term perspective by considering joint probabilities of marrying or cohabiting by certain ages and maintaining the unions for at least 8, 12, or even 24 years. We use data for female respondents in the 1979 National Longitudinal Survey of Youth to estimate choice models for multiple stages of the union-forming process. We then use the estimated parameters to simulate each woman’s sequence of union transitions from ages 18–46, and use the simulated outcomes to predict probabilities that women with given characteristics follow a variety of long-term paths. We find that a typical, 18 year-old woman with no prior unions has a 22 % chance of cohabiting or marrying within 4 years and maintaining the union for 12+ years; this predicted probability remains steady until the woman nears age 30, when it falls to 17 %. We also find that unions entered via cohabitation contribute significantly to the likelihood of experiencing a long-term union, and that this contribution grows with age and (with age held constant) as women move from first to second unions. This finding reflects the fact that the high probability of entering a cohabiting union more than offsets the relatively low probability of maintaining it for the long-term. Third, the likelihood of forming a union and maintaining it for the long-term is highly sensitive to race, but is largely invariant to factors that can be manipulated by public policy such as divorce laws, welfare benefits, and income tax laws.