Bayesian confidence interval for difference of the proportions in a 2×2 table with structural zero

This article studies the construction of a Bayesian confidence interval for risk difference in a 2×2 table with structural zero. The exact posterior distribution of the risk difference is derived under the Dirichlet prior distribution, and a tail-based interval is used to construct the Bayesian confidence interval. The frequentist performance of the tail-based interval is investigated and compared with the score-based interval by simulation. Our results show that the tail-based interval at Jeffreys prior performs as well as or better than the score-based confidence interval.     

Nonparametric validation of similar distributions and assessment of goodness of fit

In this paper the problem of assessing the similarity of two cumulative distribution functions F and G is considered. An asymptotic test based on an α-trimmed version of Mallows distance Γ_α( F , G ) between F and G is suggested, thus demonstrating the similarity of F and G within a preassigned Γ_α( F , G ) neighbourhood at a controlled type I error rate. The test proposed is applied to the validation of goodness of fit and for the nonparametric assessment of bioequivalence. It is shown that Γ_α( F , G ) can be interpreted as average and population equivalence. Our approach is illustrated by various examples.     

A test for independence in a multivariate exponential distribution with equal correlation coefficients

A rank statistic is considered which may be used for testing for total independence in a p-variate exponential distribution with equal correlation coefficients. Critical values for the statistic are provided for p = 3.4 and sample sizes less than or equal to 20. Finally, the small sample power performance of the rank test relative to that of the locally most powerful similar lest under the exponential alternative is evaluated.     

Generalized kernel regression estimator for dependent size-biased data

This paper considers nonparametric regression estimation in the context of dependent biased nonnegative data using a generalized asymmetric kernel. It may be applied to a wider variety of practical situations, such as the length and size biased data. We derive theoretical results using a deep asymptotic analysis of the behavior of the estimator that provides consistency and asymptotic normality in addition to the evaluation of the asymptotic bias term. The asymptotic mean squared error is also derived in order to obtain the optimal value of smoothing parameters required in the proposed estimator. The results are stated under a stationary ergodic assumption, without assuming any traditional mixing conditions. A simulation study is carried out to compare the proposed estimator with the local linear regression estimate.     

Mean estimation through proportion estimation

In this work a device which changes the problem of mean estimation into that of proportion estimation is proposed. The device consists of perturbing the observations. The goal of the work is the construction of conservative confidence intervals for means. Three applications are given: (1) proportion estimation in the context of cluster random sampling, (2) differences of proportions of a multinomial population and (3) variance estimation.     

Empirical bayes approach to parameter identification in linear stochastic difference equations

Empirical Bayesian parameter estimators and predictors for linear stochastic difference equations are constructed and discussed. Some properties as consistency and asymptotic optimality are investigated. The given methods are illustrated by the example of a univariate first order autoregressive process.     

The new unified representation of multivariate skewed distributions

There are so many proposals in construction skewed distributions, and it is worth finding an overall class which covers all of these proposals. We introduce a new unified representation of multivariate skewed distributions. We will show that this new unified multivariate form of skewed distributions includes all of the continuous multivariate skewed distributions in the literature. This new unified representation is based on the multivariate probability integral transformation and can be decomposed into one factor that is original multivariate symmetric probability density function (pdf) f on ? ^k and skewed factor defined by a pdf p on [0, 1] ^k . This decomposition leads us to prove some useful properties of this new unified form. Stochastic representations and basic properties of this new form are also investigated in this article. Our work is motivated by considering the different skewing mechanisms which lead to different skewed distributions and show that all of these common-used distributions can be viewed as a new unified form.     

The Diffusion of Innovations: A Methodological Reappraisal

Studies of diffusion have traditionally relied on specific distributions, primarily the logistic, to characterize and estimate those processes. We argue that such an approach gives rise to serious problems of comparability and interpretation and may result in large biases in the estimates of the parameters of interest. We propose instead the Gini's expected mean difference as a measure of diffusion speed. We discuss its advantages over the traditional approach, present a nonparametric estimation procedure, and tackle with it the problems of truncated processes and of intergroup comparisons. We also elaborate on the use of the hazard rate and suggest various extensions. The diffusion of computed tomography scanners is presented as an illustration.     

农业区域经济差异对农业经济增长影响的实证研究——以新疆为例

区域经济差异是影响经济增长的关键因素,这种影响可能是积极的,也可能是消极的。以新疆1988-2004年14个地区的截面和时序数据为例,结合多元统计分析方法、库兹涅茨系数和分形理论,实证分析农业区域经济差异的现状及其影响因素,研究发现农业结构的不平衡、农业资源禀赋等差异导致了农业区域经济增长差距逐步拉大。     

农地抵押贷款试点政策对农民收入的增长效应研究

文章基于2013—2019年湖南省县域面板数据,采用双重差分方法识别了农地抵押贷款试点对农民收入增长的效应。研究发现:政策对农民收入增长效应显著为正,效果提高约3.84%,以多种稳健性检验,此结论依然成立。这一政策对邻近区县具有正向溢出效应,政策效果非贫困区县强于贫困区县。此外,农地抵押贷款试点主要通过农业扶持、产业扶持、金融扶持、城市化提升等措施对当地农民收入产生间接影响,更重要的是,政策通过相应精准扶持措施促进政策效应,但仍然需要降低融资壁垒,促进农村金融农地抵押融资。研究结果进一步强调了农地抵押贷款试点需根据地区实际发展情况,因时因地因户精准施策的重要性。