Sample Size Formulas for Normal Theory T Tests

Formulas that yield minimum sample size for standard T tests are presented. Although the results are approximations, they usually yield the exact solution. Involving only standard normal quantiles, they could be used in an elementary course.     

The Information Geometric Structure of Generalized Empirical Likelihood Estimators

The generalized empirical likelihood (GEL) method produces a class of estimators of parameters defined via general estimating equations. This class includes several important estimators, such as empirical likelihood (EL), exponential tilting (ET), and continuous updating estimators (CUE). We examine the information geometric structure of GEL estimators. We introduce a class of estimators closely related to the class of minimum divergence (MD) estimators and show that there is a one-to-one correspondence between this class and the class GEL.     

Moderate wage increases and flexible labour contracts to protect employment in Colombian manufacturing

Based on conditional and unconditional demands for labour, we exploit the variations of real minimum wage across manufacturing subsectors to present evidence that this variable affects formal employment. The long-term elasticity of labour demand to the minimum wage is around –0.7. Accordingly, increases in the minimum wage lead to job losses for unskilled labour, mainly in plants with fewer than 100; thus, small increases in the minimum wage are desirable to protect employment. Labour demand is highly cyclical: the output elasticity is about 1.7. Thus, some flexibility in labour contracts is desirable to reduce the link between employment and variation of plants’ sales. Open-ended labour contracts might allow reductions of the nominal wage rather than inducing job losses during periods of severe slumps, as has happened during the COVID-19 pandemic.     

Using Data Envelopment Analysis (DEA) for monitoring efficiency-based performance of productivity-driven organizations: Design and implementation of a decision support system

The competitive nature of the business environment requires the productivity-driven organization to be aware of its relative level of effectiveness and efficiency vis-à-vis its competitors. This suggests the need, first, for an effective mechanism that allows for discovering appropriate productivity models for improving overall organizational performance, and, second for a feedback-type mechanism that allows for evaluating multiple productivity models in order to select the most suitable one. In this paper our focus is on organizations that consider the states of their internal (e.g., possibly exemplified by resource-based view) and external (e.g., possibly exemplified by positioning) organizational environment in the formulation of their strategies. We propose and test a DEA-centric Decision Support System (DSS) that aims to assess and manage the relative performance of such organizations.     

一个新的银行信用风险评估方法

本文以银行信用风险管理为例,将粗糙集和决策树两种具有互补优势的数据挖掘方法相结合,对客户信用做出归类分析判断,最后利用决策树生成决策规则.实践证明,这种方法忠于原始数据,提高了分类准确度,减小了决策树规模,具有良好的性能.     

An Information Theoretic Framework for Exploratory Multivariate Market Segmentation Research*

State-of-the-art market segmentation often involves simultaneous consideration of multiple and overlapping variables. These variables are studied to assess their relationships, select a subset of variables which best represent the subgroups (segments) within a market, and determine the likelihood of membership of a given individual in a particular segment. Such information, obtained in the exploratory phase of a multivariate market segmentation study, leads to the construction of more parsimonious models. These models have less stringent data requirements while facilitating substantive evaluation to aid marketing managers in formulating more effective targeting and positioning strategies within different market segments. This paper utilizes the information-theoretic (IT) approach to address several issues in multivariate market segmentation studies. A marketing data set analyzed previously is employed to examine the suitability and usefulness of the proposed approach [12]. Some useful extensions of the IT framework and its applications are also discussed.     

The Effects of Minimum Wage Increases on Retail Employment and Hours: New Evidence from Monthly CPS Data

Proponents of state and federal minimum wage increases argue that past minimum wage hikes have not adversely affected retail employment. However, the existing empirical evidence is mixed. This study uses monthly data from the 1979–2004 Current Population Survey to provide new estimates of the effect of minimum wage increases on retail employment and hours worked. The findings suggest evidence of modest adverse effects. A 10% increase in the minimum wage is associated with a 1% decline in retail trade employment and usual weekly hours worked. Larger negative employment and hours effects are observed for the least experienced workers in the retail sector. These results are robust across a number of specifications, but are sensitive to controls for state time trends.

论社会工作在农村最低生活保障漏洞治理中的作用

社工介入到农村最低生活保障活动,可避免熟人社会中某些习俗的影响,避免救助对象不当受益问题,通过收集信息来完善低保标准,避免超标受益、重复受益等漏洞问题;专业社工通过增能来帮助困难群体来表达福利诉求等。     

Tree-structured generalized autoregressive conditional heteroscedastic models

We propose a new generalized autoregressive conditional heteroscedastic (GARCH) model with tree-structured multiple thresholds for the estimation of volatility in financial time series. The approach relies on the idea of a binary tree where every terminal node parameterizes a (local) GARCH model for a partition cell of the predictor space. The fitting of such trees is constructed within the likelihood framework for non-Gaussian observations: it is very different from the well-known regression tree procedure which is based on residual sums of squares. Our strategy includes the classical GARCH model as a special case and allows us to increase model complexity in a systematic and flexible way. We derive a consistency result and conclude from simulation and real data analysis that the new method has better predictive potential than other approaches.     

推广的Hadamard码的研究

本文研究了推广的Hadamard码C的最小距离问题,讨论了推广的Hadamard码C是F_2~n上的码,码长为n,维数为2(n+1),并证明了推广的Hadamard码C的最小距离为(n-3)/2.