A note on the equality of the OLSE and the BLUE of the parametric function in the general Gauss–Markov model

In this note we consider the equality of the ordinary least squares estimator (OLSE) and the best linear unbiased estimator (BLUE) of the estimable parametric function in the general Gauss–Markov model. Especially we consider the structures of the covariance matrix V for which the OLSE equals the BLUE. Our results are based on the properties of a particular reparametrized version of the original Gauss–Markov model.      

Estimating a sensitive proportion through randomized response procedures based on auxiliary information

Randomized response techniques are widely employed in surveys dealing with sensitive questions to ensure interviewee anonymity and reduce nonrespondents rates and biased responses. Since Warner’s (J Am Stat Assoc 60:63–69, 1965) pioneering work, many ingenious devices have been suggested to increase respondent’s privacy protection and to better estimate the proportion of people, π _A , bearing a sensitive attribute. In spite of the massive use of auxiliary information in the estimation of non-sensitive parameters, very few attempts have been made to improve randomization strategy performance when auxiliary variables are available. Moving from Zaizai’s (Model Assist Stat Appl 1:125–130, 2006) recent work, in this paper we provide a class of estimators for π _A , for a generic randomization scheme, when the mean of a supplementary non-sensitive variable is known. The minimum attainable variance bound of the class is obtained and the best estimator is also identified. We prove that the best estimator acts as a regression-type estimator which is at least as efficient as the corresponding estimator evaluated without allowing for the auxiliary variable. The general results are then applied to Warner and Simmons’ model.     

Estimation of a relative potency of two preparations with correlated responses

Estimation of a relative potency of two preparations in so-called parallel-line assays is presented. A special type of incomplete Latin square designs where doses of preparations are administered is considered. Testing hypotheses about similarity of preparations and their relative potency in the case of correlated observations are regarded. Confidence interval for the relative potency of preparations is also given. Theoretical considerations are applied to point and interval estimation of potencies of new tuberculins with respect to some international standards tested in experiments on guinea-pigs.     

Nonparametric density deconvolution by weighted kernel estimators

Nonparametric density estimation in the presence of measurement error is considered. The usual kernel deconvolution estimator seeks to account for the contamination in the data by employing a modified kernel. In this paper a new approach based on a weighted kernel density estimator is proposed. Theoretical motivation is provided by the existence of a weight vector that perfectly counteracts the bias in density estimation without generating an excessive increase in variance. In practice a data driven method of weight selection is required. Our strategy is to minimize the discrepancy between a standard kernel estimate from the contaminated data on the one hand, and the convolution of the weighted deconvolution estimate with the measurement error density on the other hand. We consider a direct implementation of this approach, in which the weights are optimized subject to sum and non-negativity constraints, and a regularized version in which the objective function includes a ridge-type penalty. Numerical tests suggest that the weighted kernel estimation can lead to tangible improvements in performance over the usual kernel deconvolution estimator. Furthermore, weighted kernel estimates are free from the problem of negative estimation in the tails that can occur when using modified kernels. The weighted kernel approach generalizes to the case of multivariate deconvolution density estimation in a very straightforward manner.     

质量建设是辅导员队伍建设的根本

辅导员工作在高校思想政治工作中居于重要地位。在新的历史时期,辅导员工作内容发生了根本性的改变,要求其从业人员具有更高的综合素质。加强辅导员队伍质量建设已成为高校思想政治工作中亟待解决的问题。     

英国农村发展模式对中国新农村建设的启示

农村发展模式是指农村发展的样式及所呈现的特点。在这个意义上,英国的农村发展道路走的是典型的内发变迁模式,即结合本国实际情况主要依靠本国自身力量来实现农业现代化和城乡一体化的一种方式。在中国建设社会主义新农村的关键时期,针对中国新农村建设在资金、组织方式等方面的实际情况和问题,英国农村发展模式的特征及经验,具有有益的借鉴启示。     

Race and opportunity in a public alternative school

This qualitative case-study explores questions about the stratifying role of public alternative schools created for ‘at-risk’ youth by analyzing the school experience of students who attend a single continuation high school and the process of student enrollment and referral to that school. Drawing on the concept of whiteness as property, this article demonstrates how the continuation high school maintained and protected the property functions of whiteness through acts of symbolic violence and the systematic removal of non-white students from the school district’s mainstream high school. Instead, students were placed in a substandard alternative school lacking in material and intellectual resources. Furthermore, teachers, counselors, and administrative staff at the mainstream and continuation high schools alike drew upon the racial ideology of merit to rationalize the overrepresentation of non-white youths at the study school and to ‘deracialize’ the student referral process.     

Emotions and cosmopolitan sociability: Barriers and opportunities for intercultural encounters amongst new Chinese migrants in New Zealand

Emotions matter, particularly in experiences of migration. This article explores how emotions are involved in everyday intercultural encounters and the role of emotions in generating cosmopolitan sociability in the context of migration. The article is based upon qualitative research with 80 Chinese 1st and 1.5 generation migrants in New Zealand. We focus on ‘contact zones’ as social spaces where migrants have uneven opportunities to encounter cultural others and where ‘emotional dissonance’ can emerge through unsuccessful intercultural exchanges. In order to generate a sense of comfort and familiarity in such conflicted spaces, migrants need to invest in ‘emotional labour’ to engage in more cosmopolitan sociability as an attempt to transform ‘contact zone’ to ‘comfort zone’. Through this article we argue that emotions can both promote and encourage, but also undermine and limit the capacity to perform cosmopolitan sociability and build intercultural relations.     

Bullying and Victimization Among Young Elementary School Children: The Role of Child Ethnicity and Ethnic School Composition

School-aged children with an ethnic minority background are relatively often involved in bullying and victimization, but the role of ethnic composition of schools in this context remains unclear. This study examined the relation between ethnic minority background, ethnic school composition, and bullying behaviour around primary school entry in the Netherlands. The study was based on a 2008/2009 school survey in Rotterdam, a Dutch city where about 50 % of children have a non-Dutch background. For 8523 children, teacher reports of bullying behaviour at age 5–6 years were available. Children with a non-Dutch background had higher odds of being a victim (adjusted OR 1.41, 95 % CI 1.11, 1.80), bully (OR 1.38, 95 % CI 1.20, 1.58) or bully-victim (OR 1.38, 95 % CI 1.19, 1.62) than children of Dutch national origin. Ethnic diversity in schools increased children’s risk of bullying behaviour (e.g. OR_victim per 0.1 increase in 0–1 diversity range = 1.06, 95 % CI 1.00, 1.13), with children of both Dutch and non-Dutch national origin relatively more often involved in bullying in ethnically diverse schools. The proportion of same-ethnic peers in school reduced the risk of bullying among children of Dutch national origin (e.g. OR_victim per 10 % more same-ethnic children = 0.90, 95 % CI 0.83, 0.98), but not among non-Dutch children. In conclusion, ethnic minority background and ethnic diversity within schools are risk factors for bullying among 5–6 year olds. Plausibly, reductions in absolute numbers of bullying events may be obtained with tailor-made interventions in ethnically diverse schools. Such interventions should preferably be offered early in the school curriculum.     

Wealth Inequality in Black and White: Cultural and Structural Sources of the Racial Wealth Gap

Using data from the 2013 Survey of Consumer Finances, this research examines competing and complementary cultural and structural explanations of the sources of racial differences in wealth. We use OLS regression and quantile regression to identify the major individual-level sources of wealth differences between African Americans and whites. Whites have more favorable wealth characteristics than do African Americans on all of the variables in the analysis: gender of household head, bankruptcies, spending patterns, stock ownership, business ownership, home ownership, inheritance, educational attainment, income, occupation, age, and number of children. Cultural factors, having a female-headed family, spending patterns, and inheritance account for little of the racial wealth gap. Racial differences in income, stock ownership, and business ownership account for much of the explained racial wealth gap. Moreover, compared with whites, African Americans receive significantly lower wealth returns to education, age, income, stock ownership, and business ownership. We discuss the implications of our findings.