Seeing through Statistics

Abstract

Introduction to Graphical Modelling by David Edwards, New York: Springer-Verlag, 1995, 274 pp. Reviewed by Garry Robins

Introduction to Graphical Modelling by David Edwards, New York: Springer-Verlag, 1995, 274 pp. Reviewed by Garry Robins

Graphical Models by Steffen L. Lauritzen, Oxford, U.K.: Clarendon Press, 1996, 298 pp. Reviewed by Garry Robins     

Correcting Statistics for Delayed Data

Journal of the Operational Research Society - This note indicates an approach to adjusting the statistical records of the number of basic operations of an organisation to allow for delays in...     

Languages for Statistics and Data Analysis

Abstract

Languages for data analysis and statistics must be able to cover the entire spectrum from improvisation and fast prototyping to the implementation of streamlined, specialized systems for routine analyses. Such languages must not only be interactive but also programmable, and the distinctions between language, operating system, and user interface get blurred. The issues are discussed in the context of natural and computer languages, and of the different types of user interfaces (menu, command language, batch). It is argued that while such languages must have a completely general computing language kernel, they will contain surprisingly few items specific to data analysis—the latter items more properly belong to the “literature” (i.e., the programs) written in the language.     

Scan Statistics for Normal Data with Outliers

Methodology and Computing in Applied Probability - In this article we investigate the performance of scan statistics based on moving medians, as test statistics for detecting a local change in...     

可靠性统计分析中“倒挂”数据的处理方法

在贮存可靠性中,经常会出现“倒挂”数据.本文讨论了“倒挂”数据的处理方法.在合适的数学模型下,用Bayes方法得到了一些有用的结果.     

Rule Induction for Group Decisions with Statistical Data — An Example

An expert system was desired for a group decision-making process. A highly variable data set from previous groups' decisions was available to simulate past group decisions. This data set has much missing information and contains many possible errors. Classification and regression trees (CART) was selected for rule induction, and compared with multiple linear regression and discriminant analysis. We conclude that CART's decision rules can be used for rule induction. CART uses all available information and can predict observations with missing data. Errors in results from CART compare well with those from multiple linear regression and discriminant analysis. CART results are easier to understand.     

Data Analysis and Statistics in Middle Grades: An Analysis of Content Standards

The purpose of the study reported herein was to identify the important aspects of statistical knowledge that students in the middle school grades in United States are expected to learn as well as what the teachers are expected to teach. A systematic study of 49 states standards and one set of national standards was used to identify these important aspects, and to measure the degree of emphasis or importance suggested for the content. Results show that state and national standards differ greatly in their expectations of what topics in data analysis and statistics students and teachers should master. There is also a large variation in the degree of emphasis given to the content. The majority of the standards analyzed suggest giving greater emphasis to the selection and proper use of graphical data representation and measures of center.     

基于贝叶斯统计方法的两总体基因表达数据分类

在疾病的诊断过程中,对疾病的精确分类是提高诊断准确率和疾病治愈率至 关重要的一个环节,DNA芯片技术的出现使得我们从微观的层次获得与疾病分类及诊断 密切相关的基因功能信息．但是DNA芯片技术得到的基因的表达模式数据具有多变量小 样本特点,使得分类过程极不稳定,因此我们首先筛选出表达模式发生显著性变化的基因 作为特征基因集合以减少变量个数,然后再根据此特征基因集合建立分类器对样本进行分 类．本文运用似然比检验筛选出特征基因,然后基于贝叶斯方法建立了统计分类模型,并 应用马尔科夫链蒙特卡罗(MCMC)抽样方法计算样本归类后验概率．最后我们将此模型 应用到两组真实的DNA芯片数据上,并将样本成功分类．     

房地产业上市公司的统计数据挖掘分析研究

应用统计类数据挖掘技术对房地产业上市公司财务进行了分析。即搜集十五个房地产业上市公司的主要财务指标进行因子分析,用提取主成份的方法缩减变数,归纳出影响公司财务状况的四个主要因素。然后,对十五家房地产上市公司进行聚类分析,划分各公司的经营等级。最后,结合因子分析与聚类分析的结果对各公司的经营状况进行了综合评价,并以此指导投资者和经营管理者做出正确的决策。     

“Decisions,Decisions.....”

The decision analyst can provide valuable support to the decisionmaking process and, increasingly, the impact of this support is becoming more forceful through the use of decision support software packages available on microcomputers. What are the opportunities for using decision support software and what software is currently available? This paper discusses these questions and outlines the part decision support software can play, its value to the decisionmaker, and some of the pitfalls in practical application.     

Optimal Investment Decisions

A discrete investment model of a production project is considered. Stoppage and recovery of production are allowed. The project is scrapped if the maintenance costs exceed some limit. The optimal maintenance cost threshold is calculated.     

Operational Decisions in AGV-Served Flowshop Loops: Scheduling

This paper considers operational issues that arise in repetitive manufacturing systems served by automated guided vehicles (AGVs) in loops with unidirectional material flow. The objective considered is the minimization of the steady state cycle time required to produce a minimal job set (or equivalently, throughput rate maximization). Our models allow for delays caused by AGV conflicts. We define and analyze three nondominated and widely used AGV dispatching policies. For each policy, we describe algorithms and intractability results for combined job scheduling and material handling problems. We describe a genetic algorithm that estimates the cycle time within 5% on average for instances with up to 10 machines and four AGVs. Some related fleet sizing and loop decomposition issues are discussed in the companion paper [19].