共查询到20条相似文献,搜索用时 25 毫秒
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R.J. Ellis 《Serials Review》2013,39(1):15-28
AbstractStandards are essential to guide both technical and information management in providing access to and delivery of content. Standards development, implementation, and use help the information community meet the needs of its users. The information community grapples with a myriad of methods for providing access to content and capturing transaction level information about access to and use of content. Publishers struggle with ways to manage increased content flow. The author discusses the 2002 revision of the Standard for Library Statistics, NISO Z39.7 (NISO is the National Information Standards Organization, a nonprofit association founded in 1939 and accredited by the American National Standards Institute (ANSI)), and the research and assessment that went into its evolution from a static index of data elements to a Web-based data dictionary embracing U.S. and international metrics for describing and measuring information services and delivery. 相似文献
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ABSTRACTCylindrical data are bivariate data from the combination of circular and linear variables. However, up to now no work has been done on the detection of outlier in cylindrical data. We introduce a definition of outlier for cylindrical data and present a new test of discordancy to detect outlier in this type of data, based on the k-nearest neighbor’s distance. Cut-off points of the new test statistic based on the Johnson-Wehrly distribution are calculated and its performance is examined using simulation. A practical example is presented using wind speed and wind direction data obtained from the Malaysian Meteorological Department. 相似文献
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Lynn Roy LaMotte 《统计学通讯:理论与方法》2020,49(13):3126-3136
AbstractType III methods were introduced by SAS to address difficulties in dummy-variable models for effects of multiple factors and covariates. They are widely used in practice; they are the default method in several statistical computing packages. Type III sums of squares (SSs) are defined by a set of instructions; an explicit mathematical formulation does not seem to exist.An explicit formulation is derived in this paper. It is used to illustrate Type III SSs and to establish their properties in the two-factor ANOVA model. 相似文献
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ABSTRACTConstrained general linear models (CGLMs) have wide applications in practice. Similar to other data analysis, the identification of influential observations that may be potential outliers is an important step beyond in the CGLMs. We develop multiple case-deletion diagnostics for detecting influential observations in the CGLMs. The diagnostics are functions of basic building blocks: studentized residuals, error contrast matrix, and the inverse of the response variable covariance matrix. The basic building blocks are computed only once from the complete data analysis and provide information on the influence of the data on different aspects of the model fit. Computational formulas are given which make the procedures feasible. An illustrative example with a real data set is also reported. 相似文献
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AbstractIn this work, we establish exponential inequalities for the Robbins–Monro’s algorithm with ψ-mixing variables, and we give a result on the almost complete convergence rate. 相似文献
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《Journal of Statistical Computation and Simulation》2012,82(1-2):147-158
In a recent paper (J. Statist. Comput. Simul., 1995, Vol.53, pp. 195–203) P. A. Wright proposed a new process capability index Cs which generalizes the Pearn-Kotz-Johnson’s index Cpmk by taking into account the skewness (in addition to deviation of the mean from tliCrntarget already incorporated in Cpmk ). The purpose of this article is to study the consistency and asymptotics of an estimate ?s of Cs The asymptotic distribution provides an insight into some desirable properties of the estimate which are not apparent from its original definition 相似文献
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AbstractIn this paper, we consider the preliminary test approach to the estimation of the regression parameter in a multiple regression model under multicollinearity situation. The preliminary test almost unbiased two-parameter estimators based on the Wald, the Likelihood ratio, and the Lagrangian multiplier tests are given, when it is suspected that the regression parameter may be restricted to a subspace and the regression error is distributed with multivariate Student’s t errors. The bias and quadratic risk of the proposed estimators are derived and compared. Furthermore, a Monte Carlo simulation is provided to illustrate some of the theoretical results. 相似文献
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Every random q-vector with finite moments generates a set of orthonormal polynomials. These are generated from the basis functions xn = xn11…xnqq using Gram–Schmidt orthogonalization. One can cycle through these basis functions using any number of ways. Here, we give results using minimum cycling. The polynomials look simpler when centered about the mean of X, and still simpler form when X is symmetric about zero. This leads to an extension of the multivariate Hermite polynomial for a general random vector symmetric about zero. As an example, the results are applied to the multivariate normal distribution. 相似文献
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Tetsuji Ohyama 《统计学通讯:理论与方法》2020,49(10):2529-2539
AbstractScott’s pi and Cohen’s kappa are widely used for assessing the degree of agreement between two raters with binary outcomes. However, many authors have pointed out its paradoxical behavior, that comes from the dependence on the prevalence of a trait under study. To overcome the limitation, Gwet [Computing inter-rater reliability and its variance in the presence of high agreement. British Journal of Mathematical and Statistical Psychology 61(1):29–48] proposed an alternative and more stable agreement coefficient referred to as the AC1. In this article, we discuss a likelihood-based inference of the AC1 in the case of two raters with binary outcomes. Construction of confidence intervals is mainly discussed. In addition, hypothesis testing, and sample size estimation are also presented. 相似文献
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本文建立了现金股利与企业价值的联立方程,用二阶段最小二乘法分析了我国特有的股权结构下二者之间的关系。研究结果表明,现金股利支付率与企业价值负相关、与管理层持股比例负相关。 相似文献
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《统计学通讯:理论与方法》2012,41(2):454-470
AbstractWhen the elements of a random vector take any real values, formulas of product moments are obtained for continuous and discrete random variables using distribution/survival functions. The random product can be that of strictly increasing functions of random variables. For continuous cases, the derivation based on iterated integrals is employed. It is shown that Hoeffding’s covariance lemma is algebraically equal to a special case of this result. For discrete cases, the elements of a random vector can be non-integers and/or unequally spaced. A discrete version of Hoeffding’s covariance lemma is derived for real-valued random variables. 相似文献
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Shivangi Singh 《统计学通讯:理论与方法》2019,48(10):2562-2579
In a recent paper, Nourbakhsh and Yari (2017) introduce the weighted version of Renyi’s entropy for left/right truncated random variables and studied their properties in context of reliability analysis. In the present communication we extend the notion of weighted Renyi’s entropy for two-sided truncated random variable. In reliability theory and survival analysis, this measure may help to study the quantitative-qualitative information spectrum of a system/component when it fails between two time points. Various aspects of weighted Renyi’s interval entropy have been discussed and some mistakes in the preceding literature have also been corrected. These results generalize and enhance the related existing results that are developed based on weighted Renyi’s entropy for one-sided truncated random variable. Finally, a simulation study is added to provide the estimates of the proposed measure and to demonstrate the performance of the estimates. 相似文献
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本文首先介绍新修订的国际收支表涉及贸易项目的调整要点,提出应重视加工贸易从货物转移到服务项下核算引起的对中国贸易平衡的影响。接着以主要篇幅对此进行测算和分析,得出影响虽然不小,但不会颠覆货物贸易平衡格局的结论。最后提出关于服务贸易理论和统计制度的四点思考。 相似文献
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ABSTRACTThe correlation coefficient (CC) is a standard measure of a possible linear association between two continuous random variables. The CC plays a significant role in many scientific disciplines. For a bivariate normal distribution, there are many types of confidence intervals for the CC, such as z-transformation and maximum likelihood-based intervals. However, when the underlying bivariate distribution is unknown, the construction of confidence intervals for the CC is not well-developed. In this paper, we discuss various interval estimation methods for the CC. We propose a generalized confidence interval for the CC when the underlying bivariate distribution is a normal distribution, and two empirical likelihood-based intervals for the CC when the underlying bivariate distribution is unknown. We also conduct extensive simulation studies to compare the new intervals with existing intervals in terms of coverage probability and interval length. Finally, two real examples are used to demonstrate the application of the proposed methods. 相似文献
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《The American statistician》2012,66(4):408-410
AbstractFeng et al. revealed that the usual mean value theorem (MVT) should not be applied directly to a vector-valued function (e.g., the score function or a general estimating function under a multiparametric model). This note shows that the application of the Cramer–Wold’s device to a corrected version of the MVT is sufficient to obtain standard asymptotics for the estimators attained from vector-valued estimating functions. 相似文献
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Mariusz Bieniek 《统计学通讯:理论与方法》2013,42(22):6641-6650
ABSTRACTWe derive sharp upper and lower projection bounds on the bias of two-sided Winsorized means. To determine the projection of appropriate function, we consider new analytic condition which describes the form of the corresponding greatest convex minorant. Then we compare numerically obtained bounds for trimmed and Winsorized means. We conclude that if we have no information about the underlying distribution then Winsorized means are better than the trimmed ones. 相似文献