A Small Sample Test for the Equality of Intraclass Correlation Coefficients Under Unequal Family Sizes for Several Populations

The set of all distinct blocks of a BIBD(v,b,r,k,λ) is referred to as the support of the design. In this paper, the family of BIB designs with v=9 and k=3 is studied from the view of possible support sizes, b*'s. A table is constructed of designs with support sizes belonging to {12,18,20,21,…,84}, for minimum possible b in each case and for any larger admissible b. In constructing this table the methods of trade-off and composition of designs are utilized     

A Method for Analyzing Supersaturated Designs with a Block Orthogonal Structure

Supersaturated designs is a large class of factorial designs which can be used for screening out the important factors from a large set of potentially active variables. The huge advantage of these designs is that they reduce the experimental cost drastically, but their critical disadvantage is the confounding involved in the statistical analysis. In this article, we propose a method for analyzing data using a specific type of supersaturated designs. This method heavily uses the special block orthogonal structure of the supersaturated designs given by Tang and Wu (1997 Tang , B. , Wu , C. F. J. ( 1997 ). A method for constructing supersaturated designs and its Es ²-optimality . Canadian J. Statist. 25 : 191 – 201 .[Crossref], [Web of Science ®] , [Google Scholar]). Also, we compare our method with several known statistical analysis methods by using some of the existing supersaturated designs. The comparison is performed by some simulating experiments and the Type I and Type II error rates are calculated. The results are presented in tables and the discussion to follow.     

Empirical Study of Six Tests for Equality of Populations with Zero-Inflated Continuous Distributions

We evaluated the properties of six statistical methods for testing equality among populations with zero-inflated continuous distributions. These tests are based on likelihood ratio (LR), Wald, central limit theorem (CLT), modified CLT (MCLT), parametric jackknife (PJ), and nonparametric jackknife (NPJ) statistics. We investigated their statistical properties using simulated data from mixed distributions with an unknown portion of non zero observations that have an underlying gamma, exponential, or log-normal density function and the remaining portion that are excessive zeros. The 6 statistical tests are compared in terms of their empirical Type I errors and powers estimated through 10,000 repeated simulated samples for carefully selected configurations of parameters. The LR, Wald, and PJ tests are preferred tests since their empirical Type I errors were close to the preset nominal 0.05 level and each demonstrated good power for rejecting null hypotheses when the sample sizes are at least 125 in each group. The NPJ test had unacceptable empirical Type I errors because it rejected far too often while the CLT and MCLT tests had low testing powers in some cases. Therefore, these three tests are not recommended for general use but the LR, Wald, and PJ tests all performed well in large sample applications.     

Exact Likelihood Ratio Testing for Homogeneity of the Exponential Distribution

The aim of this article is to discuss homogeneity testing of the exponential distribution. We introduce the exact likelihood ratio test of homogeneity in the subpopulation model, ELR, and the exact likelihood ratio test of homogeneity against the two-components subpopulation alternative, ELR2. The ELR test is asymptotically optimal in the Bahadur sense when the alternative consists of sampling from a fixed number of components. Thus, in some setups the ELR is superior to frequently used tests for exponential homogeneity which are based on the EM algorithm (like the MLRT, ADDS, and D-tests). One important example of superiority of ELR and ELR2 tests is the case of lower contamination. We demonstrate this fact by both theoretical comparisons and simulations.     

Statistical Analysis for the Inverse Trinomial Distribution

This article considers parameter estimation, goodness of fit, likelihood ratio and score tests, and model selection by Akaike information criterion for the inverse trinomial (IT) distribution, a classical one-dimensional random walk distribution. The IT distribution has a cubic variance function of the mean and is a generalization of the negative binomial distribution. Basic distributional properties and expressions for the probability mass function, recurrence formula, moments, and score functions are also presented.     

金融发展、城镇化与贫困减缓--基于系统GMM的估计

采用1978-2010年中国省际面板数据,运用系统GMM估计对金融发展（金融规模和金融效率）、城镇化与贫困减缓的关系进行经验检验。研究结果表明：城镇化与贫困减缓均具有时间的积累和持续性;金融发展与城镇化、贫困减缓具有显著的正相关关系,随着经济的增长变化,金融发展能够显著提高城镇化进程,进而促进贫困减缓。与金融规模相比较,金融效率的城镇化和贫困减缓效应偏小。     

中国银行业全面对外开放水平的基本判断与分析

正确测度、判断中国银行业的对外开放水平,是确保我国银行业乃至整个金融业在对外开放过程中发展、稳定与安全的前提和基础。为达此目的,本文首先给出了中国银行业对外开放的评价指标体系,在此基础上构建了能全面、准确衡量中国银行业对外开放水平的测度模型;借助于该模型,本文对中国银行业对外开放水平进行了测度与判断。研究结果表明:与自身相比,中国银行业的对外开放水平一直处于上升状态,且在入世过渡期间上升幅度迅速加大;而与成熟的美国银行业相比,中国银行业全面对外开放水平还不高,仍有较大差距。最后,基于本文对中国银行业全面对外开放水平的判断,提出了相应的对策建议。     

A Performance Measure for Software Reuse Projects

The efficient development of software has become a critical factor to the success of many organizations. Significant competitive advantage can be realized by reducing the time to complete software development, while maintaining or improving quality levels. Project management activities, including the measurement of performance at the level of the project, can help the organization to both control projects and learn from experience. Traditionally, the productivity of a software development project has been measured as the complexity of code produced per unit of labor involved. An increasing number of organizations, however, are adopting the practice of software reuse, and under such conditions, such a traditional measure of productivity does not fully capture all the relevant elements of the reuse-driven development environment. This research develops a new performance measure that considers four major components of performance: productivity associated with development of new code, productivity associated with the reuse of previously written code, quality of the reuse decision, and relative value of reuse to the company. To illustrate the feasibility of the measure, a real-world productivity assessment is presented for an example company, and related implementation issues are discussed.     

Axiomatic Justification for a Geometric Quality Aggregation Function

A central issue in many decision-making situations is the need to consider multiple factors. A special case of multifactor modeling is the quality aggregation problem, which is to derive an overall quality measurement from a set of component quality measurements. Although much research has been published regarding the components of a quality construct, alternative methods for aggregating quality components have been largely ignored. The function generally used for this aggregation is an arithmetic weighted average. This article proposes four axioms that are intuitively desirable in a quality aggregation function. Concepts are drawn from related disciplines such as utility theory, decision theory, and microeconomics. Empirical evidence is presented to support the axioms. The arithmetic weighted average function is found to be inconsistent with all four axioms. A geometric, or multiplicative, function form is presented as a superior alternative, consistent with the four axioms. Model specification issues and other implications are discussed.     

Multiple Conceptualizations of Small Business Web Use and Benefit*

Small businesses play an important role in the U.S. economy and there is anecdotal evidence that use of the Web is beneficial to such businesses. There is, however, little systematic analysis of the conditions that lead to successful use of and thereby benefits from the Web for small businesses. Based on the innovation adoption, organizations, and information systems (IS) implementation literature, we identify a set of variables that are related to adoption, use, and benefits of information technology (IT), with particular emphasis on small businesses. These variables are reflective of an organization's contextual characteristics, its IT infrastructure, Web use, and Web benefits. Since the extant research does not suggest a single theoretical model for Web use and benefits in the context of small businesses, we adopt a modeling approach and explore the relationships between “context‐IT‐use‐benefit” (CIUB) through three models—partial‐mediator, reduced partial‐mediator, and mediator. These models posit that the extent of Web use by small businesses and the associated benefits are driven by organizations’ contextual characteristics and their IT infrastructure. They differ in the endogeneity/exogeneity of the extent of IT sophistication, and in the direct/mediated effects of organizational context. We examine whether the relationships between variables identified in the literature hold within the context of these models using two samples of small businesses with national coverage, including various sizes, and representing several industry sectors. The results show that the evidence for patterns of relationships is similar across the two independent samples for two of these models. We highlight the relationships within the reduced partial‐mediator and mediator models for which conclusive evidence are given by both samples. Implications for small business managers and providers of Web‐based technologies are discussed.