The Effect of Methods for Handling Missing Values on the Performance of the MEWMA Control Chart

This article is concerned with the effect of the methods for handling missing values in multivariate control charts. We discuss the complete case, mean substitution, regression, stochastic regression, and the expectation–maximization algorithm methods for handling missing values. Estimates of mean vector and variance–covariance matrix from the treated data set are used to build the multivariate exponentially weighted moving average (MEWMA) control chart. Based on a Monte Carlo simulation study, the performance of each of the five methods is investigated in terms of its ability to obtain the nominal in-control and out-of-control average run length (ARL). We consider three sample sizes, five levels of the percentage of missing values, and three types of variable numbers. Our simulation results show that imputation methods produce better performance than case deletion methods. The regression-based imputation methods have the best overall performance among all the competing methods.     

The derivation of a brief Student Nurse Stress Index

The lack of an adequate measure of perceived sources of stress for student nurses led to the construction of the Student Nurse Stress Index (SNSI). Responses from 235 first-year student nurses to 35 items from the Beck and Srivastava Stress Inventory (Beck, and Srivastava, 1991), and 15 new items, were subjected to exploratory factor analysis using principal components analysis and oblimin rotation. A reliable 22-variable solution with a simple oblique structure including Academic load, Clinical sources, Interface worries, and Personal problems factors was obtained in this initial sample, and confirmed at an exploratory level in a further independent validation sample of 188 first-year students. Confirmatory factor analysis established the four-factor model in the first sample, but required that three variables load onto more than one factor. This more complex four-factor model was confirmed using independent data from the validation sample, and the total invariance of factor loadings and factor covariances of this more complex four-factor model was established in both data sets simultaneously using multi-sample techniques. The SNSI shows cross-sample factor congruence, good internal reliabilities, and concurrent and discriminant validity across a range of reporting conditions.     

Leerstände: A Photo Project

ABSTRACT

Contrary to previous belief, there are now known to be substantial numbers of household inventories for nineteenth-century England and Wales. This article discusses what, and how, this “new” source can add to our understanding of the domestic cultures of the period. It describes how these inventories, read through the lens of a material-culture approach in both aggregate and interpretive analysis, not only offer unprecedented grounded evidence for how a sample of “unremarkable” Victorians laid out and equipped the spaces of their homes but also bring to light stories of intention, choice, and change in the furnishing, equipment, use, and meaning of domestic spaces.     

Estimation of Location Parameters Under Nonnormal Errors and Quadratic Loss

Assuming a statistical model in which the joint distribution of the unobservable errors is drawn from independent univariate Student t's that are identically and symmetrically distributed, the sampling performance of traditional robust estimators and a family of Stein-like estimators are compared and evaluated. These results suggest that under thick-tailed distributions, the relative sampling performances and risk characteristics for a range of nonconventional Stein estimators remains approximately the same as in the case of their normal counterparts. The empirical risk implications of misspecifying the error distribution are investigated.     

学籍管理的电子信息化

对电子信息化的学籍档案管理工作模式进行了初步探讨。从学籍信息获取、维护、查询以及交换方面进行了详细描述,并结合典型校园网信息平台的特点,给出了关键部分的实现方式,提出了实现以上方案所需的关键条件。最后对学籍管理电子信息的前景做了展望。     

再析表见代理性质与被代理人过失

表见代理虽发生有权代理的效果 ,但将其归为有权代理却有诸多弊端 ,将其认定为无权代理则更具有合理性。对于表见代理是否应以被代理人过失为要件 ,应视构成表见代理的各种情形而定。     

A hazard model of the probability of medical school drop-out in the UK

Summary.  From individual level longitudinal data for two entire cohorts of medical students in UK universities, we use multilevel models to analyse the probability that an individual student will drop out of medical school. We find that academic preparedness—both in terms of previous subjects studied and levels of attainment therein—is the major influence on withdrawal by medical students. Additionally, males and more mature students are more likely to withdraw than females or younger students respectively. We find evidence that the factors influencing the decision to transfer course differ from those affecting the decision to drop out for other reasons.     

转型时期学校组织地位的重新确认——论高等院校的第三部门属性

在计划经济体制的影响下,一直以来我们都将教育事业及学校看成附属于政府部门的事业单位,这种定位是导致政府对学校管理高度集权的直接原因。然而在社会经济体制转型的过程中,教育越来越突显它的独立性。市场经济所产生的社会结构变化要求建立一种新的理论思路来对学校,特别是高等院校进行重新定位,这不仅给高校管理注入了新的理念,而且有助于推动高校管理体制的改革。本文从教育的功能及性质等方面阐述了将高校定位于第三部门组织的必要性及可行性。     

关于两类矛盾问题的沉思

人民内部矛盾问题提出的初衷是为了区分两类不同性质的矛盾 ,用说服和教育的方法来解决人民内部矛盾。可是自从这个理论提出后不久 ,就开始了全国范围大规模持续不断地混淆两类矛盾的历史。教训是多方面的 ,但最重要的是没有适时地提出依法治国和建设社会主义法制国家的口号 ,中国传统的人治思想遮蔽了人们的视线。在依法治国的今天 ,如何区分两类矛盾问题已经有法可依 ,而正确处理人民内部矛盾的思想对于我们处理多方面复杂的社会矛盾 ,化解冲突 ,避免发生危及社会安全的重大事件 ,保持社会的稳定 ,仍具有重要的指导意义     

高职生心理问题及教育对策浅议

提高高职生心理健康水平,不仅是高职生成人之需要,更是高职院校教育任务之必要。本文分析了高职学生的心理问题及主要表现,对其产生原因进行了探讨,并结合实际,就心理问题的对策提出了一些思考。