Richard G. Spencer  Benjamin D. Cortese  Vanessa A. Lukas  Nancy Pleshko 《The American statistician》2017,71(1):81-87

In a wide variety of biomedical and clinical research studies, sample statistics from diagnostic marker measurements are presented as a means of distinguishing between two populations, such as with and without disease. Intuitively, a larger difference between the mean values of a marker for the two populations, and a smaller spread of values within each population, should lead to more reliable classification rules based on this marker. We formalize this intuitive notion by deriving practical, new, closed-form expressions for the sensitivity and specificity of three different discriminant tests defined in terms of the sample means and standard deviations of diagnostic marker measurements. The three discriminant tests evaluated are based, respectively, on the Euclidean distance and the Mahalanobis distance between means, and a likelihood ratio analysis. Expressions for the effects of measurement error are also presented. Our final expressions assume that the diagnostic markers follow independent normal distributions for the two populations, although it will be clear that other known distributions may be similarly analyzed. We then discuss applications drawn from the medical literature, although the formalism is clearly not restricted to that application.  相似文献   

    

D. Malathi  S. Muthulakshmi 《Journal of applied statistics》2017,44(2):376-384

In this article designing of acceptance sampling plans for the truncated life test is proposed using economic approach by assuming that the lifetime of a product follows Frechet distribution based on median. The optimal sampling plans to meet the consumer’s confidence level with minimum total cost are designed. Efficiency of the proposed plan is also analyzed.  相似文献   

    

Eudoxia Kakarantza  Spyridon D. Symeonides 《Journal of applied statistics》2017,44(4):667-684

A generalization of Zellner's SUR model is derived for sets of seemingly unrelated systems of econometric equations. The resulting structural form – worked out for a set of Cowles Commission-type simultaneous equations systems – is general enough to include any SUR-type or panel-type specification of systems of econometric equations with contemporaneously correlated errors. Maximum estimation efficiency is obtained by treating all the individual subsystems at once rather than in a subsystem-by-subsystem fashion.  相似文献   

    

Michele Nguyen  Almut E. D. Veraart 《Scandinavian Journal of Statistics》2017,44(1):46-80

Spatio‐temporal modelling is an increasingly popular topic in Statistics. Our paper contributes to this line of research by developing the theory, simulation and inference for a spatio‐temporal Ornstein–Uhlenbeck process. We conduct detailed simulation studies and demonstrate the practical relevance of these processes in an empirical study of radiation anomaly data. Finally, we describe how predictions can be carried out in the Gaussian setting.  相似文献   

    

David D. Hanagal  Arvind Pandey  P. G. Sankaran 《统计学通讯:模拟与计算》2017,46(1):230-243

Frailty models are used in the survival analysis to account for the unobserved heterogeneity in the individual risks to disease and death. To analyze the bivariate data on related survival times (e.g., matched pairs experiments, twin or family data), the shared frailty models were suggested. In this article, we introduce the shared gamma frailty models with the reversed hazard rate. We develop the Bayesian estimation procedure using the Markov chain Monte Carlo (MCMC) technique to estimate the parameters involved in the model. We present a simulation study to compare the true values of the parameters with the estimated values. We apply the model to a real life bivariate survival dataset.  相似文献   

    

Derek M. D. Silva 《Sociological Forum》2017,32(1):138-161

In this article, I engage with Edward Said's Orientalism and various perspectives within the othering paradigm to analyze the emergence and transformation of radicalization discourses in the news media. Employing discourse analysis of 607 New York Times articles from 1969 to 2014, this article demonstrates that radicalization discourses are not new but are the result of complex sociolinguistic and historical developments that cannot be reduced to dominant contemporary understandings of the concept or to singular events or crises. The news articles were then compared to 850 government documents, speeches, and other official communications. The analysis of the data indicates that media conceptualizations of radicalization, which once denoted political and economic differences, have now shifted to overwhelmingly focus on Islam. As such, radicalization discourse now evokes the construct radicalization as symbolic marker of conflict between the West and the East. I also advanced the established notion that the news media employ strategic discursive strategies that contribute to conceptual distinctions that are used to construct Muslims as an “alien other” to the West.  相似文献   

    

Daniel D. Dieringer  Janet G. Lenz  Seth C. W. Hayden  Gary W. Peterson 《The Career development quarterly》2017,65(2):159-172

Although some research literature focuses on the integration of mental health and career counseling, there has been little that examines both areas in relation to depression and hopelessness. This study investigated the relationship among dysfunctional career thinking, depression, and hopelessness in a sample of 139 undergraduate and graduate students seeking drop‐in or individual career counseling services at a university career center. The authors found that two aspects of dysfunctional career thinking, decision‐making confusion and commitment anxiety, accounted for a significant amount of variance in depression. Decision‐making confusion also accounted for a significant amount of variance in hopelessness. Implications for counseling practice include the need for more careful screening of career clients who present with high levels of anxiety and negative thinking. Future research could involve more diverse client populations, such as unemployed adults, and explore the use of additional screening measures to assess the intersection of career and mental health issues.  相似文献   

    

David D. Dobrzykowski  Kathleen L. McFadden 《决策科学》2020,51(1):74-109

Governance can be challenging in healthcare operations, particularity when attending physicians lack financial relationships with the hospital. In the absence of formal incentive system mechanisms, it may be possible to use informal relational governance to synchronize activities. We use Relational Resource Based View and Agency theory to conceptualize trust (an informal governance mechanism) and physician employment (a formal governance mechanism) as moderators of key operational phenomena in hospitals. Specifically, we test the moderated effects of trust and physician employment on the relationships among lean strategy, process integration, operational efficiency, and patient satisfaction. Analysis of 583 data points from 302 acute care U.S. hospitals reveals that lean strategy impacts process integration, and process integration impacts operational efficiency and patient satisfaction. Trust enhances the positive relationship between lean strategy and process integration such that the relationship is stronger when physicians are employed by the hospital and weaker when physicians are not employed by the hospital. A post hoc analysis reveals that physician employment also influences how process integration affects patient satisfaction. Our results explain the key roles of trust, physician employment, and integration in linking strategy and outcomes. Practitioner interviews validate and help to tease out the implications of our findings. This study contributes important insights for researchers, executives, and policy makers interested in governance and improvements in healthcare delivery.  相似文献   

    

Pablo D. Fajgelbaum  Edouard Schaal 《Econometrica : journal of the Econometric Society》2020,88(4):1411-1452

We study optimal transport networks in spatial equilibrium. We develop a framework consisting of a neoclassical trade model with labor mobility in which locations are arranged on a graph. Goods must be shipped through linked locations, and transport costs depend on congestion and on the infrastructure in each link, giving rise to an optimal transport problem in general equilibrium. The optimal transport network is the solution to a social planner's problem of building infrastructure in each link. We provide conditions such that this problem is globally convex, guaranteeing its numerical tractability. We also study cases with increasing returns to transport technologies in which global convexity fails. We apply the framework to assess optimal investments and inefficiencies in the road networks of European countries.  相似文献   

    

Margarita M. Castillo  Iván D. Sánchez  Sebastian Dueñas-Ocampo 《Business and Society Review》2020,125(3):329-348

The worldwide problem of corruption is one that requires greater knowledge about responsible leadership. Based on the literature on responsible leadership, developmental psychology, and moral development, the purpose of our study is to understand the constructions of the motivational drivers behind the behaviors of a responsible leader. Using biographical and narrative methodologies, we analyzed the individual motivational drivers of Carlos Cavelier, a recognized responsible leaders who grew up and works in Colombia, a social/economic context characterized by institutional fragility and corruption. Our findings suggest that the coherence between the immediate environments of development of the future leader, configured optimal environments in which the leader developed the moral conscience that guides his behavior as a responsible leader. Our study points out the need not to take the development of responsible leaders for granted, and presents propositions that allow for a deeper understanding of the micro-foundations of responsible leadership, highlighting the importance of the contexts in which leaders are raised and in which they develop. Thus, our study has the potential to be heuristic and generative of future studies.  相似文献