Two point priors and Γ-minimax estimating in families of uniform distributions

It is shown that when a parameter lying in a sufficiently small interval is to be estimated in a family of uniform distributions, a two point prior is least favourable under squared error loss. The unique Bayes estimator with respect to this prior is minimax. The Γ-minimax estimator is derived for sets Γ of priors consisting of all priors that give fixed probabilities to two specified subintervals of the parameter space if a two point prior is least favourable in Γ.     

Parental income and the fruits of labor: Variability in homework efficacy in secondary school

Research in the sociology of education has shown that noncognitive traits are important predictors of educational outcomes and a mechanism of the intergenerational transmission of status. However, previous research on this topic typically posits that there is a constant effect of these traits with variable prevalences of these traits by socioeconomic status. Using time spent on homework as an example, I analyze income-based heterogeneity in homework efficacy, defined as the individual effect of study time on academic achievement, using a national U.S. probability sample of secondary students. Higher income students gain more knowledge from their homework time than their counterparts in all grades and all subjects except history, with greater group differences for math than for science and reading. These results are confirmed by models accounting for time-invariant unobserved heterogeneity in the 8th–10th, but not 10th–12th, grade windows. These results imply that increases in the amount of homework assigned may increase the socioeconomic achievement gap in math, science, and reading in secondary school.     

浦东农村集体建设用地流转研究

当前,浦东集体建设用地低效、闲置和浪费现象比较普遍,资产价值尚未真正体现,尤其是乡镇工业用地聚集度低,布局分散,点多规模小,建筑密度和容积率低;工业产出率不高,厂房、场地闲置严重。通过集体建设用地的流转,实施土地二次开发,可以有效利用存量用地,盘活土地资源。要通过确权登记发证,进一步理清产权界限,避免产权主体虚置与权能重叠;建立合理的收益分配机制,确保农民利益;加快相关财政体制衔接．保障流转工作有序推进。     

Letting Students Control Their Own Learning: Using Games,Role-Plays,and Simulations in Middle School U.S. History Classrooms

The purpose of this article is to synthesize research on the benefits and use of games, role-plays, and simulations, whilst providing examples practicing teachers may wish to use in their classroom. Therefore, the article presents a discussion of key previous research on the use of games, role-plays, and simulations in secondary history classrooms. It also presents a discussion of the benefits games, role-plays, and simulations can have on student learning. This includes discussion of how such student-centered teaching and learning opportunities can improve students' critical thinking, problem-solving, and collaborative skills. Finally, it presents examples of these types of student-centered, inquiry-based, hands-on learning experiences, drawn from the author's previous 16 years of secondary classroom experiences.     

Semiparametric inference of proportional odds model based on randomly truncated data

This paper studies the estimation in the proportional odds model based on randomly truncated data. The proposed estimators for the regression coefficients include a class of minimum distance estimators defined through weighted empirical odds function. We have investigated the asymptotic properties like the consistency and the limiting distribution of the proposed estimators under mild conditions. The finite sample properties were investigated through simulation study making comparison of some of the estimators in the class. We conclude with an illustration of our proposed method to a well-known AIDS data.     

Decomposing primary and secondary effects: A new decomposition method

One strand of educational inequality research aims at decomposing the effect of social class origin on educational choices into primary and secondary effects. We formalize this distinction and present a new and simple method that allows empirical assessment of the relative magnitudes of primary and secondary effects. Contrary to other decomposition methods, this new method is unbiased, is more intuitive, and decomposes effects of both discrete and continuous measures of social origin. The method also provides analytically derived statistical tests and is easily calculated with standard statistical software. We give examples using the Danish Longitudinal Survey of Youth.     

A Comparison of Survival Function Estimators in the Koziol–Green Model

In this paper, three competing survival function estimators are compared under the assumptions of the so-called Koziol– Green model, which is a simple model of informative random censoring. It is shown that the model specific estimators of Ebrahimi and Abdushukurov, Cheng, and Lin are asymptotically equivalent. Further, exact expressions for the (noncentral) moments of these estimators are given, and their biases are analytically compared with the bias of the familiar Kaplan–Meier estimator. Finally, MSE comparisons of the three estimators are given for some selected rates of censoring.     

Modified minimax estimation of regression coefficients

Working with the linear regression model (1.1) and having the extraneous information (1.2) about regression coefficients the problem exists how to build estimators (1.3) with the risk (1.4) which enable to utilize the known information in order to reduce their risk as compared with the risk (1.6) of the LSE (1.5). Solution of this problem is known for the positive definite matrix T, namely in form for estimators (1.8) and (1.10).First, it is shown that the proposed estimators (2.6),(2.9) and (2.16) based on psedoinversions of the matrix L represent the solution of the problem of the positive semidefinite matrix T=L'L.Further, the problem of interpretability of estimators in the sense of the inequality (3.1) exists; it is shown that all mentioned estimators are at least partially interpretable in the sense of requirements (3.2) or (3.10).     

高校心理辅导站建立的初步探析

高校心理辅导站的建立为心理健康教育提供了新的平台,它的优势是显而易见的。本文阐述了心理辅导站建立的意义、定位及作用,并对辅导站的发展瓶颈及对策进行了初步探究。