线性模型中相关附加信息全部损失的条件(英文)

通过讨论回归系数的混合估计和Bayes估计的相关附加信息全部损失的条件,本文给出了线性模型中选择相关附加样本应遵守的一个原则,并研究了两个应用问题。     

英国的绥靖政策探析

二战爆发前后，英国鉴于自身国力衰 落，为保全其世界霸权地位，对法西斯德国采取了绥靖政策，它与英国传统的均势外交政策是连续性与中断性的统一。     

The causal effect of an extra year of schooling on skills and knowledge in Latin America. Evidence from PISA

Abstract

In this paper, we estimate the causal effect of an extra year of schooling on mathematics performance for seven Latin American countries based on PISA 2012. To that end we exploit exogenous variation in students’ birthdates around the school entry cut-off date using both sharp and fuzzy Regression Discontinuity designs. We find strong effects of an extra year of schooling in most countries, which amount to a 30% increase in PISA test scores in Brazil, 18% in Uruguay, 7% in Argentina and 6% in Costa Rica. These effects differ from the typical estimates obtained from simple regressions or multilevel models and are large enough to allow 15-year-old students to reach higher proficiency levels, suggesting significant potential gains of reducing dropout rates in the region. Finally, we stress the importance of taking into account the effects of school entry cut-off dates on PISA samples to avoid making unfair international comparisons.     

从女子标枪成绩的多元回归分析中看样本含量与F 的取值对结论的影响

以女子标枪6 个变量因素为例, 对三组不同样本含量和F 的取值进行了多元回归分析, 结果表明: 在样本的成绩范围内, 样本n = 10 建立的“最优”回归方程与样本n = 60 , n = 30 的结论基本相同. 认为用样本n = 10建立“最优”回归方程既方便又省力. 强调在作逐步回归分析时, F 的检验临界值要取低些, 并指出: 在指标因素过多时, 应先聚类, 然后分别选出影响最大的指标建立“最优”方程.     

对陈独秀中止国共"党内合作"主张的再认识

陈独秀曾极力反对国共"党内合作",后来又几次提出中共党员退出国民党的主张.其原因是随着革命的深入发展,国共关系日趋恶化,陈独秀感到国共"党内合作"的基础已遭到破坏.但国共"党内合作"是历史的选择,并且由于共产国际的坚决反对和中国革命的指导者采取了机会主义的平衡策略,从而使国共"党内合作"得以维持下来.     

Regression through the Origin

This article describes situations in which regression through the origin is appropriate, derives the normal equation for such a regression and explains the controversy regarding its evaluative statistics. Differences between three popular software packages that allow regression through the origin are illustrated using examples from previous issues of Teaching Statistics.     

关于函数可积性与原函数存在性问题

本文结合实例探讨了函数的可积性与原函数的存在性之间的相互关系。     

千山决明子总黄酮含量的测定

利用分光光度法，测定了千山决明子总黄酮的含量，建立了芦丁浓度—吸光度关系的回归方程。     

Regression Discontinuity Designs With Multiple Rating-Score Variables

Abstract

In the absence of a randomized control trial, regression discontinuity (RD) designs can produce plausible estimates of the treatment effect on an outcome for individuals near a cutoff score. In the standard RD design, individuals with rating scores higher than some exogenously determined cutoff score are assigned to one treatment condition; those with rating scores below the cutoff score are assigned to an alternate treatment condition. Many education policies, however, assign treatment status on the basis of more than one rating-score dimension. We refer to this class of RD designs as “multiple rating score regression discontinuity” (MRSRD) designs. In this paper, we discuss five different approaches to estimating treatment effects using MRSRD designs (response surface RD; frontier RD; fuzzy frontier RD; distance-based RD; and binding-score RD). We discuss differences among them in terms of their estimands, applications, statistical power, and potential extensions for studying heterogeneity of treatment effects.     

Search engines’ responses to several search feature selections

The authors of this paper investigated the impact of the advanced search features of three common search engines on retrieval result performance: Yahoo, Google, and Live Search. The authors analyzed 240 search queries with different information need emphases to determine retrieval effectiveness differences among regular search, title search, exact phrase search, and PDF file format restriction search. A one-way ANOVA method and regression analysis method were used for the study. It was found that the PDF file format restriction search achieved the best retrieval performance among Yahoo, Google and Live Search. The regular search achieved the best web page ranking performance among Yahoo, Google, and Live Search. The findings of this study can be used to assist users in formulating an appropriate search strategy to improve search effectiveness, and to shed light on how search engines react to different types of search features in terms of retrieval effectiveness.