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51.
We introduce a family of Rényi statistics of orders r?∈?R for testing composite hypotheses in general exponential models, as alternatives to the previously considered generalized likelihood ratio (GLR) statistic and generalized Wald statistic. If appropriately normalized exponential models converge in a specific sense when the sample size (observation window) tends to infinity, and if the hypothesis is regular, then these statistics are shown to be χ2-distributed under the hypothesis. The corresponding Rényi tests are shown to be consistent. The exact sizes and powers of asymptotically α-size Rényi, GLR and generalized Wald tests are evaluated for a concrete hypothesis about a bivariate Lévy process and moderate observation windows. In this concrete situation the exact sizes of the Rényi test of the order r?=?2 practically coincide with those of the GLR and generalized Wald tests but the exact powers of the Rényi test are on average somewhat better.  相似文献   
52.
D. Morales  L. Pardo  I. Vajda 《Statistics》2013,47(2):151-174
Rényi statistics are considered in a directed family of general exponential models. These statistics are defined as Rényi distances between estimated and hypothetical model. An asymptotically quadratic approximation to the Rényi statistics is established, leading to similar asymptotic distribution results as established in the literature for the likelihood ratio statistics. Some arguments in favour of the Rényi statistics are discussed, and a numerical comparison of the Rényi goodness-of-fit tests with the likelihood ratio test is presented.  相似文献   
53.
In this paper we consider the problem of testing hypotheses in parametric models, when only the first r (of n) ordered observations are known.Using divergence measures, a procedure to test statistical hypotheses is proposed, Replacing the parameters by suitable estimators in the expresion of the divergence measure, the test statistics are obtained.Asymptotic distributions for these statistics are given in several cases when maximum likelihood estimators for truncated samples are considered.Applications of these results in testing statistical hypotheses, on the basis of truncated data, are presented.The small sample behavior of the proposed test statistics is analyzed in particular cases.A comparative study of power values is carried out by computer simulation.  相似文献   
54.
It is becoming increasingly common to hear life scientists say that high quality life science research relies upon high quality laboratory animal care. However, the idea that animal care is a crucial part of scientific knowledge production is at odds with previous social science and historical scholarship regarding laboratory animals. How are we to understand this discrepancy? To begin to address this question, this paper seeks to disentangle the values of scientists in identifying animal care as important to the production of high quality scientific research. To do this, we conducted a survey of scientists working in the United Kingdom who use animals in their research. The survey found that being British is associated with thinking that animal care is a crucial part of conducting high quality science. To understand this finding, we draw upon the concept of ‘civic epistemologies’ (Jasanoff 2005; Prainsack 2006) and argue that ‘animals’ and ‘care’ in Britain may converge in taken‐for‐granted assumptions about what constitutes good scientific knowledge. These ideas travel through things like state regulations or the editorial policies of science journals, but do not necessarily carry the embodied civic epistemology of ‘animals’ and ‘science’ from which such modes of regulating laboratory animal welfare comes.  相似文献   
55.
Parents' differentiation has been linked to negative psychological and behavioral outcomes in children, adolescents, and young adults. This line of research, however, has not been extended to families in later life. In this article, we use data from 671 mother‐child dyads in 275 families in the greater Boston area to explore whether mothers' differentiation among their children is related to psychological well‐being among offspring. We examined actual and perceived maternal differentiation in the domains of closeness, expectations for care, and conflict. We hypothesized that depressive symptoms would be higher when mothers differentiated among their children and when adult children perceived differentiation. Although the specific patterns varied somewhat by mothers' and children's reports, the findings indicated that, across all 3 domains, maternal differentiation was related to higher depression scores.  相似文献   
56.
We consider the asymptotic distribution of divergence-based influence measures which are an extension for polytomous logistic regression of an influence measure proposed in Johnson (1985 Johnson, W.O. (1985). Influence measures for logistic regression: Another point of view. Biometrika 72: 5965.[Crossref], [Web of Science ®] [Google Scholar]), for binary logistic regression. A numerical example compares the classical Cook’s distance with the divergence based influence measures.  相似文献   
57.

Aim

To examine foot posture changes during the three trimesters of pregnancy and to determine whether there is a relationship between these changes and the pain experienced in this period.

Methods

The study sample consisted of 62 pregnant women who attended the Gynaecology Service at Hospital ?Santa María del Puerto (Cádiz, Spain), between January 2013 and May 2014. In their first visit, the following sociodemographic and anthropometric data were recorded: age, weight, height and foot size. In addition, information was obtained regarding pain in the lower back, knees, ankles and feet. In this first visit, too, the Foot Posture Index (FPI) was assessed, and three subsequent controls were performed during the first, second and third months of pregnancy (termed Stages 1, 2 and 3, respectively).

Results

In Stage 1, the average foot size (i.e., shoe size) was 38.3 (SD 1.5). This size did not change between Stages 1, 2 and 3. However, body weight and BMI did present statistically significant changes during this period (p < 0.0001). The FPI varied during pregnancy but no relation was observed between these changes and the onset of pain.

Conclusions

During pregnancy, pronation increases but this does not appear to influence the onset of pain in the lower limbs.  相似文献   
58.
This work introduces specific tools based on phi-divergences to select and check generalized linear models with binary data. A backward selection criterion that helps to reduce the number of explanatory variables is considered. Diagnostic methods based on divergence measures such as a new measure to detect leverage points and two indicators to detect influential points are introduced. As an illustration, the diagnostics are applied to human psychology data.  相似文献   
59.
African American and Latino youth who reside in inner-city communities are at heightened risk for compromised mental health, as their neighborhoods are too often associated with serious stressors, including elevated rates of poverty, substance abuse, community violence, as well as scarce youth-supportive resources, and mental health care options. Many aspects of disadvantaged urban contexts have the potential to thwart successful youth development. Adolescents with elevated mental health needs may experience impaired judgment, poor problem-solving skills, and conflictual interpersonal relationships, resulting in unsafe sexual behavior and drug use. However, mental health services are frequently avoided by urban adolescents who could gain substantial benefit from care. Thus, the development of culturally sensitive, contextually relevant and effective services for urban, low-income African American and Latino adolescents is critical. Given the complexity of the mental health and social needs of urban youth, novel approaches to service delivery may need to consider individual (i.e., motivation to succeed in the future), family (i.e., adult support within and outside of the family), and community-level (i.e., work and school opportunities) clinical components. Step-Up, a high school-based mental health service delivery model has been developed to bolster key family, youth and school processes related to youth mental health and positive youth development. Step-Up (1) intervenes with urban minority adolescents across inner-city ecological domains; (2) addresses multiple levels (school, family and community) in order to target youth mental health difficulties; and (3) provides opportunities for increasing youth social problem-solving and life skills. Further, Step-Up integrates existing theory-driven, evidence-based interventions. This article describes Step-Up clinical goals, theoretical influences, as well as components and key features, and presents preliminary data on youth engagement for two cohorts of students.  相似文献   
60.
Dialogic communication is being boosted by the strong development of the social web. The web 2.0 is generating significant changes in the manner that organizations engage in dialogue with their publics, opening the way towards the interactive communication. In this way, web 2.0 tools will foster the dialogic communication between museums and their publics. Through them, the relationship between museums and publics is changing towards more interactive and collaborative forms.  相似文献   
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