A new way of quantifying the symmetry of a random variable: Estimation and hypothesis testing

New measures of skewness for real-valued random variables are proposed. The measures are based on a functional representation of real-valued random variables. Specifically, the expected value of the transformed random variable can be used to characterize the distribution of the original variable. Firstly, estimators of the proposed skewness measures are analyzed. Secondly, asymptotic tests for symmetry are developed. The tests are consistent for both discrete and continuous distributions. Bootstrap versions improving the empirical results for moderated and small samples are provided. Some simulations illustrate the performance of the tests in comparison to other methods. The results show that our procedures are competitive and have some practical advantages.     

陕西能源资源产业指标对资源税调整的响应态势拟合

对所筛选出的能源资源的有关指标进行相关性分析,辨识出与资源税相关性较高的指标,进而对其进行Granger因果检验.甄别出与资源税因果关系可能性较大的变量,基于Eviews平台,通过实验进行线性曲线拟合,对这些因变量构造拟合方程,并对拟合结果进行检验.研究显示,分别构造全省煤炭采选业新增固定资产投资、规模以上煤炭采选业工业总产值、规模以上煤炭采选业工业销售产值、石油消费量、单位GDP能源消耗五个拟合方程能够较好地模拟对资源税变动的响应关系,进而为预判资源税调整后可能对能源资源产业发展所带来的变化和为采取相应的对策提供定量化的决策依据.     

能源与经济因果关系检验:回顾与展望

针对国内外能源与经济因果关系众说纷纭的现状,在总结Granger因果关系检验方法发展脉络的基础上,归纳检验变量之间因果关系的统计方法及其在国内外能源消费与经济发展关系实证检验的结果,做出四个代际划分,并按照检验因果关系四个代际的区分与相应的优劣,给出适用于时间序列和面板数据统计因果关系检验的一般步骤。同时指出面板数据、非线性因果关系检验方法将成为研究的发展方向。     

Sample size calculation for recurrent events data in one‐arm studies

In some exceptional circumstances, as in very rare diseases, nonrandomized one‐arm trials are the sole source of evidence to demonstrate efficacy and safety of a new treatment. The design of such studies needs a sound methodological approach in order to provide reliable information, and the determination of the appropriate sample size still represents a critical step of this planning process. As, to our knowledge, no method exists for sample size calculation in one‐arm trials with a recurrent event endpoint, we propose here a closed sample size formula. It is derived assuming a mixed Poisson process, and it is based on the asymptotic distribution of the one‐sample robust nonparametric test recently developed for the analysis of recurrent events data. The validity of this formula in managing a situation with heterogeneity of event rates, both in time and between patients, and time‐varying treatment effect was demonstrated with exhaustive simulation studies. Moreover, although the method requires the specification of a process for events generation, it seems to be robust under erroneous definition of this process, provided that the number of events at the end of the study is similar to the one assumed in the planning phase. The motivating clinical context is represented by a nonrandomized one‐arm study on gene therapy in a very rare immunodeficiency in children (ADA‐SCID), where a major endpoint is the recurrence of severe infections. Copyright © 2012 John Wiley & Sons, Ltd.     

基于面板数据模型的能耗与固定资产投资关系的实证研究

首先,对我国固定资产投资与能源消费之间的关系进行了机理分析,认为大规模的固定资产投资活动是造成能耗快速增长的主要原因,并且固定资产投资与能源消费之间存在一种循环关系.然后,采用面板数据模型对我国8个主要行业的固定资产投资与能源消费关系进行了实证研究.研究结果表明,固定资产投资是我国能耗增长的格兰杰原因,固定资产投资与能耗增长之间存在显著的正相关性.最后,对遏制我国能耗高速增长给出了相应的政策建议.     

Human papillomavirus vaccine and Pap tests on college campuses: How do historically black colleges and universities (HBCUs) measure up?

ABSTRACT

Objective: The availability of cervical cancer prevention services at college health centers was compared between historically black colleges and universities (HBCUs) and non-HBCUs.

Methods: Four-year, non–primarily distant learning colleges, matching HBCUs with randomly selected non-HBCUs within the same states (N = 136) were examined. Data were collected (2014–2015 academic year) on the availability of human papillomavirus (HPV) vaccine and Pap tests at college health centers. HBCUs were compared with non-HBCUs using conditional logistic regression, and correlates of offering these services were identified. Results: Many institutions did not offer HPV vaccine or Pap tests. Fewer HBCUs offered HPV vaccine (18% vs 53%) and Pap tests (50% vs 76%) compared with non-HBCUs. In multivariable analyses, HBCUs remained less likely than non-HBCUs to offer HPV vaccine (odds ratio [OR] = 0.07, 95% confidence interval [CI]: 0.02–0.26) and Pap tests (OR = 0.19, 95% CI: 0.06–0.61). Conclusions: Greater effort is needed to make cervical cancer prevention services available at colleges, especially at HBCUs.     

农村社区型金融机构发展影响因素的实证分析

由于具有市场、信息、成本、区域等方面的竞争优势,农村社区型金融机构已经成为我国农村金融机构创新的首要途径。虽然自2005年以来我国不断出台相关鼓励政策和措施,但农村社区型金融机构的发展却仍然不尽如人意。为更好地促进其发展,利用向量误差修正模型,首次从定量的角度明确影响农村社区型金融机构发展的现实因素及其影响程度。研究结果表明,财政收入、城乡居民储蓄存款余额及农村居民消费水平对农村社区型金融机构的发展影响最为显著。     

The Responsible Use of Psychological Testing in Child Custody Evaluations: Selection of Tests

SUMMARY

The responsible use of psychological tests in child custody evaluations requires an advanced understanding of both psychological issues of test selection and legal criteria regarding admissibility of expert testimony. This paper discusses the psychological and legal issues associated with test selection and with admissibility of expert testimony pertaining to psychological test data. It is argued that the legal standards of relevance and helpfulness require the methodology underlying an expert's testimony to be both reliable and valid. Therefore, it is essential to select psychological tests with demonstrated reliability and validity. Case law regarding expert testimony and the integration of professional practice guidelines pertaining to the use of psychological tests with ethical standards will be discussed.     

News and Comment

Using personal narratives and research on teacher “communities of practice,” the authors outline a proactive response to high-stakes testing policies that places teacher learning at its center. Although research on the effects of these policies is mixed, the authors are troubled by the ways in which the policies have been used to strip teachers of their autonomy and the erosion of the value placed on their professional knowledge. The authors—who have both taught in urban schools where students had to pass high-stakes social studies tests to graduate—argue that teachers must work together to reclaim their role as leaders in response to the policies. They provide key questions that social studies teachers can use to guide an inquiry into the tests themselves and suggest ways to use the knowledge gained to better serve their students’ learning and raise test scores.