语言测试术语及其运用--有关语言测试术语的几点介绍

由于考试结果通常用分数来表示,因此考试的分数必须具有可解释性.而分数解释又涉及记分体制,为了使分数带有大量的信息,考试成绩在最终报道前,总要经过加权处理,等值处理,正态转换等一系列转换分析过程.作者对随之产生的有关英语测试的专业术语进行了详细的介绍,对其使用过程和作用作了详尽的分析.     

时变弹性生产函数模型统计学与经济学检验

 内容提要：本文给出时变弹性生产函数的半参数变系数Profile估计方法,提出利用统计学和经济学原理检验时变弹性生产函数显著性和准确性的新思路。中国实证研究发现,广义似然比统计检验无法拒绝 Cobb-Douglas生产函数,但是经济学检验拒绝Cobb-Douglas生产函数。时变弹性生产函数保留了Cobb- Douglas生产函数结构形式,具有明确的经济学意义,改进不变产出弹性中性技术进步假设,是更加符合实际的生产函数模型。     

Some improved estimators for a measures of dispersion of an inverse gaussian distribution

In this paper some improved estimators for the measure of dispersion of an inverse Gaussian distribution have been obtained. If some guessed value of λ is available in the form of a point esitmate λ₀ the shrikage technique has been applied and an estimator has been proposed which has smaller mean squared error than the usual estimator. Since the shrinkage estimator has better performance if the guessed value is in the vicinity of the true value, a shrinkage testimator has also been proposed and compared with the usual estimator.     

Unbiased and upper critical values of mean trace of multivariate beta for testing difference of two covariance matrices or several mean vectors

For the invariant unbiased level-α test of equality of two co-variance matrices, the quantities b and B satisfying the equations P(b≤T≤B) = 1-α, E(T|b≤T≤B) = E(T), where T is the mean trace of a multivariate beta, are required. Five and one per cent values of B are tabulated for m = 2,3(2)11,16; b can be obtained from B. Upper five and one per cent values of T are also included, as these are required for the locally most powerful invariant test of nullity of any source of difference in several mean vectors and the locally most powerful invariant one-sided test of equality of two covariance matrices. Lower critical values may be obtained from upper critical values.     

SiZer Inference for Varying Coefficient Models

Varying coefficient models are a useful statistical tool to explore dynamic patterns of a regression relationship, in which the variation features of the regression coefficients are taken as the main evidence to reflect the dynamic relationship between the response and the explanatory variables. In this study, we propose a SiZer approach as a visually diagnostic device to uncover the statistically significant features of the coefficients. This method can highlight the significant structures of the coefficients under different scales and can therefore extract relatively full information in the data. The simulation studies and real-world data analysis show that the SiZer approach performs satisfactorily in mining the significant features of the coefficients.     

Integral Representation of a Distribution Associated with a Pure Birth Process

ABSTRACT

This article deals with a distribution associated with a pure birth process starting with no individuals, with birth rates λ _n  = λ for n = 0, 2,…, m ? 1 and λ _n  = μ for n ≥ m. The probability mass function is expressed in terms of an integral that is very convenient for computing probabilities, moments, generating functions, and others. Using this representation, the kth factorial moments of the distribution is obtained. Some other forms of this distribution are also given.     

A semiparametric Bayesian approach to simplex regression model with heterogeneous dispersion

ABSTRACT

Simplex regression model is often employed to analyze continuous proportion data in many studies. In this paper, we extend the assumption of a constant dispersion parameter (homogeneity) to varying dispersion parameter (heterogeneity) in Simplex regression model, and present the B-spline to approximate the smoothing unknown function within the Bayesian framework. A hybrid algorithm combining the block Gibbs sampler and the Metropolis-Hastings algorithm is presented for sampling observations from the posterior distribution. The procedures for computing model comparison criteria such as conditional predictive ordinate statistic, deviance information criterion, and averaged mean squared error are presented. Also, we develop a computationally feasible Bayesian case-deletion influence measure based on the Kullback-Leibler divergence. Several simulation studies and a real example are employed to illustrate the proposed methodologies.     

填充等离子体介质筒慢波结构色散方程的研究

利用线性理论导出了注内外具有不同等离子体密度背景的介质筒慢波结构的色散方程，并对其进行了详细的计算和分析；由所得计算曲线可方便的确定出给定频率的此慢波结构的几何参数，为实际的工程设计提供了理论依据。     

A complete solution to the problem of robustness of Grubbs's test

Srivastava (1980) showed that Grubbs's test for detecting a univariate outlier is robust against the effect of intraclass correlation structure. Young, Pavur, and Marco (1989) extended this result by proving that both the significance level and the power of Grubbs's test remain unchanged within a wider family of dispersion matrices, introduced by Baldessari (1966) in a different context. In this note, we derive a complete solution of the problem by establishing that the characteristics of Grubbs's test are invariant with respect to a given dispersion matrix if and only if it has Baldessari's structure.