电子商务对企业定价决策的影响分析及对策

互联网的普及为买卖双方实现交易提供了便利的同时,网上的价格比较侵蚀了商品的价格底线。文章分析了电子商务对企业定价的冲击,给出了“成本透明”条件下企业定价决策的若干建议。     

明清五部朝邑县志编纂比较

明清两代朝邑县志今传较广者,分别为明韩邦靖、王学谟及清王兆鳌、朱廷模、李元春等编纂或主修。五部县志编纂目的 相似,然其编纂体例、内容特色、主导思想及成书情况等却不尽一致。比较它们的异同,从中可以看到这一时期我国古方志编 辑思想、体例变化及其发展历程。     

False discovery rate control for non-positively regression dependent test statistics

In this paper we present a modification of the Benjamini and Hochberg false discovery rate controlling procedure for testing non-positive dependent test statistics. The new testing procedure makes use of the same series of linearly increasing critical values. Yet, in the new procedure the set of p-values is divided into subsets of positively dependent p-values, and each subset of p-values is separately sorted and compared to the series of critical values. In the first part of the paper we introduce the new testing methodology, discuss the technical issues needed to apply the new approach, and apply it to data from a genetic experiment.     

Bayesian locally optimal design of knockout tournaments

The elimination or knockout format is one of the most common designs for pairing competitors in tournaments and leagues. In each round of a knockout tournament, the losers are eliminated while the winners advance to the next round. Typically, the goal of such a design is to identify the overall best player. Using a common probability model for expressing relative player strengths, we develop an adaptive approach to pairing players each round in which the probability that the best player advances to the next round is maximized. We evaluate our method using simulated game outcomes under several data-generating mechanisms, and compare it to random pairings, to the standard knockout format, and to two variants of the standard format.     

Cognitive and Emotional Representations of Terror Attacks: A Cross-Cultural Exploration

A questionnaire measuring cognitive and affective representations of terror risk was developed and tested in Turkey and Israel. Participants in the study were university students from the two countries (n= 351). Four equivalent factors explained terror risk cognitions in each sample: costs, vulnerability, trust, and control. A single negative emotionality factor explained the affective component of terror risk representations in both samples. All factors except control could be measured reliably. Results supported the validity of the questionnaire by showing expected associations between cognitions and emotions, as well as indicating gender differences and cultural variations. Current findings are discussed in relation to previous results, theoretical approaches, and practical implications.     

Robust pairwise multiple comparisons under short-tailed symmetric distributions

In one-way ANOVA, most of the pairwise multiple comparison procedures depend on normality assumption of errors. In practice, errors have non-normal distributions so frequently. Therefore, it is very important to develop robust estimators of location and the associated variance under non-normality. In this paper, we consider the estimation of one-way ANOVA model parameters to make pairwise multiple comparisons under short-tailed symmetric (STS) distribution. The classical least squares method is neither efficient nor robust and maximum likelihood estimation technique is problematic in this situation. Modified maximum likelihood (MML) estimation technique gives the opportunity to estimate model parameters in closed forms under non-normal distributions. Hence, the use of MML estimators in the test statistic is proposed for pairwise multiple comparisons under STS distribution. The efficiency and power comparisons of the test statistic based on sample mean, trimmed mean, wave and MML estimators are given and the robustness of the test obtained using these estimators under plausible alternatives and inlier model are examined. It is demonstrated that the test statistic based on MML estimators is efficient and robust and the corresponding test is more powerful and having smallest Type I error.     

Improved bonferroni procedures for testing overall and pairwise homogeneity hypotheses

Simes' (1986) improved Bonferroni test is verified by simulations ^?to control the α-level when testing the overall homogeneity hypothesis with all pairwise t statistics in a balanced parallel group design. Similarly, this result was found to hold (for practical purposes) in various underlying distributions other than the normal and in some unbalanced designs. To allow the use of step-up procedures based on pairwise t statistics, simulations were used to verify that Simes' test, when applied to testing multiple subset homogeneity hypotheses with pairwise t statistics also keeps the level ? α. Some robustness as above was found here too. Tables of the simulation results are provided and an example of a step-up Hommel-Shaffer type procedure with pairwise comparisons is given.     

Micro‐level dynamics of social assistance receipt: Evidence from four European countries

This study investigated the monthly dynamics of social assistance benefit receipt – in particular the incidence of long‐term benefit receipt – in four European countries: Luxembourg, The Netherlands, Norway and Sweden. The analysis is based on four separate administrative panel data sets, each covering the 96‐month period from January 2001 to December 2008. Benefit dynamics were found to vary considerably across countries. In the two Nordic countries, long‐term benefit receipt was found to be a rare exception. Most recipients, however, had multiple spells and the majority of benefit leavers returned to benefits within a few months of leaving. In Luxembourg and The Netherlands, long‐term benefit receipt was frequent, but benefit leavers were much less likely to return to benefit receipt after exit. The total duration of benefit receipt per individual across spells was two to three times as high in The Netherlands and Luxembourg as in Norway and Sweden.     

Multiple comparisons of exponential location parameters with a control based on doubly censored sample under heteroscedasticity

In this article, a one-sample procedure for multiple comparisons of exponential location parameters with a control under heteroscedasticity is proposed. The observations are obtained by doubly censored samples. A one-sided and two-sided confidence intervals are used to perform such multiple comparisons. Statistical tables of critical values and an example of comparing four drugs in treating leukemia are provided.     

Selecting the normal population with the smallest variance: A restricted subset selection rule

Consider k( ? 2) normal populations whose means are all known or unknown and whose variances are unknown. Let σ²_[1] ? ??? ? σ_[k]² denote the ordered variances. Our goal is to select a non empty subset of the k populations whose size is at most m(1 ? m ? k ? 1) so that the population associated with the smallest variance (called the best population) is included in the selected subset with a guaranteed minimum probability P* whenever σ²_[2]/σ_[1]² ? δ* > 1, where P* and δ* are specified in advance of the experiment. Based on samples of size n from each of the populations, we propose and investigate a procedure called R_BCP. We also derive some asymptotic results for our procedure. Some comparisons with an earlier available procedure are presented in terms of the average subset sizes for selected slippage configurations based on simulations. The results are illustrated by an example.