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91.
92.
It is often of interest to find the maximum or near maxima among a set of vector‐valued parameters in a statistical model; in the case of disease mapping, for example, these correspond to relative‐risk “hotspots” where public‐health intervention may be needed. The general problem is one of estimating nonlinear functions of the ensemble of relative risks, but biased estimates result if posterior means are simply substituted into these nonlinear functions. The authors obtain better estimates of extrema from a new, weighted ranks squared error loss function. The derivation of these Bayes estimators assumes a hidden‐Markov random‐field model for relative risks, and their behaviour is illustrated with real and simulated data. 相似文献
93.
94.
It is well known that the unimodal maximum likelihood estimator of a density is consistent everywhere but at the mode. The authors review various ways to solve this problem and propose a new estimator that is concave over an interval containing the mode; this interval may be chosen by the user or through an algorithm. The authors show how to implement their solution and compare it to other approaches through simulations. They show that the new estimator is consistent everywhere and determine its rate of convergence in the Hellinger metric. 相似文献
95.
Daniel L. Friesner 《Journal of Socio》2003,31(6):41
This paper presents an empirical methodology for examining cost-adjusting in relation to multiple-output health care providers. The methodology is subsequently implemented using a sample of California outpatient clinics. The empirical evidence is that these clinics do cost-adjust; that is, the clinics respond to low Medicare reimbursement by using lower quality to control the marginal costs of those patient groups not insured under a government-sponsored plan. In addition, clinics do not cost-adjust with respect to Medi-Cal patients, implying that various government reimbursement systems have different effects on a provider’s cost-adjusting behavior. 相似文献
96.
The Lake Pontchartrain Basin in southeast Louisiana is an estuarine watershed encompassing New Orleans, Baton Rouge, and wetlands that are an integral part of Louisiana's unique culture. In recent decades rapid growth and poorly planned development have resulted in a decrease in water quality and habitat loss, especially in St. Tammany Parish on the north shore of Lake Pontchartrain. In 1989, the Lake Pontchartrain Basin Foundation (LPBF), an environmental, non-profit organization, was formed to address and rectify environmental issues in the Basin. LPBF accomplishes its mission through programs addressing water quality, habitat protection, geographic information science, public access, and education.LPBF used the recent, rapid development occurring in St. Tammany Parish as a case study to examine the relationship between land use, water quality, and development in the Basin by investigating habitat change/urbanization, development in flood plains, and water quality. Through the integration of LPBF programs, it was found that urbanization is having a devastating impact on the parish's natural habitats and severely degrading water quality. Using these results, LPBF is educating Basin citizens on the protection of their habitats and water quality to insure that these resources may be available for future generations. 相似文献
97.
Janusz L. Wywiał 《Statistical Papers》2008,49(2):277-289
The sampling designs dependent on sample moments of auxiliary variables are well known. Lahiri (Bull Int Stat Inst 33:133–140,
1951) considered a sampling design proportionate to a sample mean of an auxiliary variable. Sing and Srivastava (Biometrika
67(1):205–209, 1980) proposed the sampling design proportionate to a sample variance while Wywiał (J Indian Stat Assoc 37:73–87,
1999) a sampling design proportionate to a sample generalized variance of auxiliary variables. Some other sampling designs
dependent on moments of an auxiliary variable were considered e.g. in Wywiał (Some contributions to multivariate methods in,
survey sampling. Katowice University of Economics, Katowice, 2003a); Stat Transit 4(5):779–798, 2000) where accuracy of some
sampling strategies were compared, too.These sampling designs cannot be useful in the case when there are some censored observations
of the auxiliary variable. Moreover, they can be much too sensitive to outliers observations. In these cases the sampling
design proportionate to the order statistic of an auxiliary variable can be more useful. That is why such an unequal probability
sampling design is proposed here. Its particular cases as well as its conditional version are considered, too. The sampling
scheme implementing this sampling design is proposed. The inclusion probabilities of the first and second orders were evaluated.
The well known Horvitz–Thompson estimator is taken into account. A ratio estimator dependent on an order statistic is constructed.
It is similar to the well known ratio estimator based on the population and sample means. Moreover, it is an unbiased estimator
of the population mean when the sample is drawn according to the proposed sampling design dependent on the appropriate order
statistic. 相似文献
98.
This article reports an ethnographic study of pre‐school children's social knowledge domains. Results show how the children's shared knowledge concerning social status and social differentiation in the group was strengthened and confirmed during a traditional teacher‐led ring game, where they were supposed to choose a friend. We suggest that from the perspective of the children, the game situation may be understood as, at the same time, a space of participation and an arena for establishing the power order. From the perspective of the teacher, pedagogical intentions may be challenged as they encounter and are mediated and interpreted by children's peer‐cultures. 相似文献
99.
Malka Gorfine Li Hsu Ross L. Prentice 《Journal of the Royal Statistical Society. Series B, Statistical methodology》2003,65(3):643-661
Summary. In many biomedical studies, covariates are subject to measurement error. Although it is well known that the regression coefficients estimators can be substantially biased if the measurement error is not accommodated, there has been little study of the effect of covariate measurement error on the estimation of the dependence between bivariate failure times. We show that the dependence parameter estimator in the Clayton–Oakes model can be considerably biased if the measurement error in the covariate is not accommodated. In contrast with the typical bias towards the null for marginal regression coefficients, the dependence parameter can be biased in either direction. We introduce a bias reduction technique for the bivariate survival function in copula models while assuming an additive measurement error model and replicated measurement for the covariates, and we study the large and small sample properties of the dependence parameter estimator proposed. 相似文献
100.
The ability to infer parameters of gene regulatory networks is emerging as a key problem in systems biology. The biochemical
data are intrinsically stochastic and tend to be observed by means of discrete-time sampling systems, which are often limited
in their completeness. In this paper we explore how to make Bayesian inference for the kinetic rate constants of regulatory
networks, using the stochastic kinetic Lotka-Volterra system as a model. This simple model describes behaviour typical of
many biochemical networks which exhibit auto-regulatory behaviour. Various MCMC algorithms are described and their performance
evaluated in several data-poor scenarios. An algorithm based on an approximating process is shown to be particularly efficient. 相似文献