Meta-analysis,pretest, and shrinkage estimation of kurtosis parameters

An asymptotic theory for the improved estimation of kurtosis parameter vector is developed for multi-sample case using uncertain prior information (UPI) that several kurtosis parameters are the same. Meta-analysis is performed to obtain pooled estimator, as it is a statistical methodology for pooling quantitative evidence. Pooled estimator is a good choice when assumption of homogeneity holds but it becomes inconsistent as assumption violates, therefore pretest and Stein-type shrinkage estimators are proposed as they combine sample and nonsample information in a superior way. Asymptotic properties of suggested estimators are discussed and their risk comparisons are also mentioned.     

Supervisor commitment to employees: Does agreement among supervisors' and employees' perceptions matter?

Using 322 matched employee–supervisor dyads, we investigate how level and direction of employee–supervisor (dis)agreement on supervisor's affective commitment to the employee relate to organizational commitment, emotional exhaustion, leader–member exchange, and job performance. Results from polynomial regression and response surface analyses indicate that level of employee–supervisor agreement matters: the most beneficial outcomes appear when supervisors and employees agree that the supervisor is highly committed to the employee whereas the least favorable outcomes appear when dyads' members agree that the supervisor has low commitment to the employee. Direction of employee–supervisor disagreement is also important as employee overestimation of supervisor commitment is associated with more favorable outcomes than employee underestimation. However, for two of the outcomes (organizational commitment and emotional exhaustion), the effect of employee–supervisor disagreement was attributable to a main effect of employee perceptions of supervisor commitment. We discuss the implications of these findings for the understanding of employee–supervisor relationships.     

Prospective study of birth interval dynamics in rural Bangladesh

Abstract A group of 209 married, fecund women in rural Bangladesh were studied prospectively for 24 months from 1969 to 1971 to define some of the biological and sociological factors relating to fertility performance. These women were selected from a larger study population of 112,000 that had been followed with a daily house-to-house vital registration programme since 1966. The selected women were interviewed bi-weekly and were asked questions about menstruation, pregnancy, lactation, husband's occupational absences, and monthly urine tests for pregnancy were taken. The results for 193 non-contracepting women revealed that the seasonal pattern of births previously observed in this population could be associated with a corresponding seasonal pattern of conceptions and that this was due to a seasonal trend in fecundability. The highest conception rates were in the coolest months of the year. Post-partum lactational amenorrhoea was very prolonged, averaging 17 months for women with a surviving child. The appearance of the first post-partum menstrual flow (onset of ovulation) also had a seasonal trend which could not be adequately explained. The median waiting time to conception, once menstruation had resumed was eight months. This interval was influenced by seasonal fluctuations, as well as by the age of women and by husbands' absences. The foetal wastage rate was 15·0 per 100 conceptions, with 62 per cent of the foetal losses occurring during the second month of gestation. Overall, the average birth interval was 33 months, with the prolonged lactational amenorrhoea accounting for almost 45 per cent of this interval. From the Department of Population Dynamics, Johns Hopkins University, School of Hygiene and Public Health, Baltimore, Maryland 21205.     

Underinvestment in a Profitable Technology: The Case of Seasonal Migration in Bangladesh

Hunger during pre‐harvest lean seasons is widespread in the agrarian areas of Asia and Sub‐Saharan Africa. We randomly assign an $8.50 incentive to households in rural Bangladesh to temporarily out‐migrate during the lean season. The incentive induces 22% of households to send a seasonal migrant, their consumption at the origin increases significantly, and treated households are 8–10 percentage points more likely to re‐migrate 1 and 3 years after the incentive is removed. These facts can be explained qualitatively by a model in which migration is risky, mitigating risk requires individual‐specific learning, and some migrants are sufficiently close to subsistence that failed migration is very costly. We document evidence consistent with this model using heterogeneity analysis and additional experimental variation, but calibrations with forward‐looking households that can save up to migrate suggest that it is difficult for the model to quantitatively match the data. We conclude with extensions to the model that could provide a better quantitative accounting of the behavior.     

A Study of An Alternative School for Pregnant and/or Parenting Teens: Quantitative and Qualitative Evidence

In response to multiple problems faced by pregnant and parenting teens, many alternative school-based comprehensive programs have been established throughout the United States. By collecting data from a sample of enrollees of such a school-based comprehensive program and comparing them with data collected from a sample of non-enrollees, the present study systematically evaluates the program. The results of the study seem to suggest that the program participants were more likely to have higher educational aspiration, better reproductive health outcomes, higher contraceptive use, and more breast-feeding practice and intention than those of their non-participating counterparts. The implications of the study findings for comprehensive school-based program for pregnant and/or parenting teens are discussed.Ruhul Amin is a Senior Fellow at the Center for Health Disparities Solutions and Senior Research Scientist in the Institute for Urban Research, Morgan State University, Baltimore, MD 21239. Dorothy C. Browne is the Director of the Institute for Urban Research, Jamir Ahmed is a research assistant at the Center for Health Disparities Solutions and Takanori Sato is research assistants at the Institute for Urban Research, Morgan State University, Baltimore, MD 21239.     

Two notions of positive ageing based on stochastic dominance

The negative effects of age on the life length of a device or positive ageing are commonly used criteria for classifying life distributions. In this paper two notions of positive ageing are considered. These are the new better (worse) than used in average conditional survival probability and harmonic new better (worse) than used in upper tail. Closure of these notions under mixture and convolution are studied. The survivals of a device subject to discrete shocks of these notions of ageing which occur according to homogeneous Poisson processes are studied. A cumulative damage model is considered. Two test statistics are proposed for the two notions of ageing.     

Preservation properties for the Laplace transform ordering of residual lives

Several preservation results for the Laplace transform ordering of residual lives (Lt−rl) are given. In particular, we show that theTt−rl-order is preserved under convolutions, mixtures and weak convergence. Some examples of interest in reliability theory are also presented.     

On the NBAFR (NWAFR) class of life distributions

Recently Loh (1984) presented a new generalization of the NBU class of life distributions called New Better than Average Failure Rate (NBAFR). In this paper several properties of this class are presented. For instance the closure property of its dual (NWAFR) under the operation of mixture is obtained and characterization of the NBAFR (NWAFR) property by using the Laplace transform and its relation to the cumulative damage model is studied. Some shock models which give rise to the NBAFR (NWAFR) class are discussed. Finally, a test statistic for testing exponentiality against the NBAFR alternatives is presented.     

Forgiveness, Reconciliation, and Shame: Three Key Variables in Reducing School Bullying

This study examined the relationships between forgiveness, reconciliation, shame and school bullying. The sample consisted of 1,875 Bangladeshi adolescents (60% girls) in grades 7 to 10 ( M = 8.28). In a structural equation model, both forgiveness and reconciliation directly predicted less bullying. In addition to the direct effect, an indirect pathway showed reconciliation reduced bullying via adaptive shame management. Shame acknowledgment predicted less bullying whereas shame displacement predicted more in accord with the shame management theory. An alternative model was also tested, which demonstrated that parental forgiveness eroded when children displaced their shame. The nature of the intersection between these two theoretically viable psychological models has implications for both restorative justice theory and practice.