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1.
The robustness of Mauchly's sphericity test criterion when sampling from a mixture of two multivariate normal distributions is studied. The distribution of the sphericity test criterion when the sample covariance matrix has a non-central Wishart density of rank one is derived in terms of Meijer's G-functions; its distribution under the mixture model is then deduced. The robustness is studied by computing actual significance levels of the test under the mixture model using the critical values under the usual normal model. 相似文献
2.
Proportional reversed hazard rate model and its applications 总被引:1,自引:0,他引:1
The purpose of this paper is to study the structure and properties of the proportional reversed hazard rate model (PRHRM) in contrast to the celebrated proportional hazard model (PHM). The monotonicity of the hazard rate and the reversed hazard rate of the model is investigated. Some criteria of aging are presented and the inheritance of the aging notions (of the base distribution) by the PRHRM is studied. Characterizations of the model involving Fisher information are presented and the statistical inference of the parameters is discussed. Finally, it is shown that several members of the proportional reversed hazard rate class have been found to be useful and flexible in real data analysis. 相似文献
3.
This paper is concerned with joint tests of non-nested models and simultaneous departures from homoskedasticity, serial independence and normality of the disturbance terms. Locally equivalent alternative models are used to construct joint tests since they provide a convenient way to incorporate more than one type of departure from the classical conditions. The joint tests represent a simple asymptotic solution to the “pre-testing” problem in the context of non-nested linear regression models. Our simulation results indicate that the proposed tests have good finite sample properties. 相似文献
4.
The maximum likelihood estimation for the critical points of the failure rate and the mean residual life function are presented
in the case of mixture inverse Gaussian model. Several important data sets are analyzed from this point of view. For each
of the data sets, Bootstrapping is used to construct confidence intervals of the critical points. 相似文献
5.
The objective of this study was to determine the impact of task information (TI) provided by an interface agent during the idea evaluation and integration step of the problem formulation stage of the problem solving process. The effectiveness assessment was based on solving diagnostic decision problems in the domain of complex industrial machinery. Ten domain experts participated in this study. Decision support was provided by a case-based reasoning system. Findings suggest that TI provided by the interface agent had no effect on the decision maker's performance, nor on the associated cognitive effort. However, a verbal protocol analysis revealed that the ten subjects used the interface agent to verify their decision processes. The results and their implications are discussed with respect to current findings in the area of decision support systems. 相似文献
6.
This paper presents a genetic algorithm (GA) for parallel redundancy optimization in series-parallel power systems exhibiting
multi-state behavior, optimizing the reliability subject to constraints. The components are binary and chosen from a list
of products available in the market, and are being characterized by their feeding capacity, reliability, cost and weight.
System reliability is defined as the ability to satisfy consumer demand and is presented as a piecewise cumulative load curve.
In GA, to handle infeasible solutions penalty strategies are used. Penalty technique keep a certain amount of infeasible solutions
in each generation so as to enforce genetic search towards an optimal solution from sides of, both, feasible and infeasible
regions. We here present a dynamic adaptive penalty function which helps the algorithm to search efficiently for optimal/near
optimal solution. To evaluate system reliability, a fast procedure, based on universal generating function, is used. An example
considering a multi-state series-parallel power system is solved considering both homogeneous and heterogeneous types of redundancy.
Also an example considering price discounts is solved. The effectiveness of the penalty function and the proposed algorithm
is studied and shown graphically. 相似文献
7.
We study nonlinear least-squares problem that can be transformed to linear problem by change of variables. We derive a general formula for the statistically optimal weights and prove that the resulting linear regression gives an optimal estimate (which satisfies an analogue of the Rao-Cramer lower bound) in the limit of small noise. 相似文献
8.
In this paper the relationships between a disruption in parental co-habitation and various categories of adolescent outcomes over multiple time horizons are explored. Using data from the National Longitudinal Study of Adolescent Health (Add Health), we estimated the effects of a change from living with both parents to just one, on academic and employment outcomes, the likelihood to indulge in risky behaviors, mental health outcomes and body mass index measures, from less than 1 year to over 14 years after the change. Propensity score matching methods were used to control for individual characteristics and pre-existing differences in the family environment that may increase the chances of separation, and the results are compared to those obtained using ordinary least squares or probit methods. Results showed evidence of adverse effects of living with one parent in the short term, medium term and long term. Adolescents living with one parent had lower academic achievement in all term lengths, poor mental health in the short to medium term, and were more likely to engage in risky behaviors in the medium to long term. 相似文献
9.
Integrating risk, gender diversity and upper echelons literatures, we examine whether the presence of women in upper management (top management team (TMT) and board of directors (BOD)) and the tenure of TMTs and BODs are associated with the risk of lawsuits. An analysis of data from firms in the US retail industry shows that the presence of women in TMTs and BODs and the tenure of TMTs and BODs are negatively associated with legal risk, but longer tenured BODs with more women had a positive impact on lawsuits. Implications and suggestions for future research are offered. 相似文献
10.