基于人体膳食均衡视角下的我国果蔬消费趋势预测与结构优化

水果和蔬菜是为人体提供矿物质、维生素、膳食纤维等营养元素的重要农产品,我国居民饮食中普遍存在着能量相对过剩、果蔬摄入量不足的问题。以人体膳食均衡为研究视角,研究我国果蔬消费趋势和结构优化问题,结果表明：按照当前的消费趋势发展,我国居民营养摄入不足与过剩同在的问题依然无法得到解决;我国政府在制定水果和蔬菜战略布局的决策中,应综合考虑人体的膳食营养均衡和未来市场营养需求,以实现我国果蔬产业布局优化;消费者在进行水果和蔬菜消费购买行为时,应在营养膳食均衡的基础上进行合理消费。     

A win ratio approach to comparing continuous non‐normal outcomes in clinical trials

Clinical trials are often designed to compare continuous non‐normal outcomes. The conventional statistical method for such a comparison is a non‐parametric Mann–Whitney test, which provides a P‐value for testing the hypothesis that the distributions of both treatment groups are identical, but does not provide a simple and straightforward estimate of treatment effect. For that, Hodges and Lehmann proposed estimating the shift parameter between two populations and its confidence interval (CI). However, such a shift parameter does not have a straightforward interpretation, and its CI contains zero in some cases when Mann–Whitney test produces a significant result. To overcome the aforementioned problems, we introduce the use of the win ratio for analysing such data. Patients in the new and control treatment are formed into all possible pairs. For each pair, the new treatment patient is labelled a ‘winner’ or a ‘loser’ if it is known who had the more favourable outcome. The win ratio is the total number of winners divided by the total numbers of losers. A 95% CI for the win ratio can be obtained using the bootstrap method. Statistical properties of the win ratio statistic are investigated using two real trial data sets and six simulation studies. Results show that the win ratio method has about the same power as the Mann–Whitney method. We recommend the use of the win ratio method for estimating the treatment effect (and CI) and the Mann–Whitney method for calculating the P‐value for comparing continuous non‐Normal outcomes when the amount of tied pairs is small. Copyright © 2016 John Wiley & Sons, Ltd.     

顾客非理性消费行为机理探析

非理性消费已经成为零售企业利润的重要来源,得到学术界的普遍关注。认为顾客非理性消费行为是受到内在的、最本质的特殊顾客需要驱使而产生的不合理行为,揭示了驱动顾客非理性消费行为的顾客需要,并探讨了情绪状态因素调节顾客需要与顾客非理性消费行为关系的作用机理。基于416份问卷的调查结果,社交需要、释压需要和求廉需要是驱使顾客产生非理性消费行为的主要内在动因,情绪对特殊的顾客需要具有不同的调节作用。旨在丰富顾客非理性消费行为的知识,为商家实施目标营销、新服务开发提供重要理论支持。     

A股上市公司变相财务操纵对行业估值的影响

关于上市公司利润操控的相关研究主要是将净利润作为一个事关操控的敏感指标,但在监管与被监管双方努力的博弈下,其可被操纵的潜力已被充分挖掘。从实证角度关注上市公司财务操纵的其他可操作途径,其中就包括一些看似合理的变相财务操纵手段。按照2001年中国证监会公布的《上市公司行业分类指引》,把我国上市企业分为13个行业,对不同行业内企业2003—2013年部分主观可操控的财务指标与其所在行业的平均市盈率进行格兰杰因果检验和回归分析,结果表明,一些行业内企业的部分财务指标与其所在行业的平均市盈率存在领先与滞后关系,并且影响作用显著。     

中国对中亚能源投资的法律问题及对策

中国与中亚在能源方面合作不断加强,逐步形成了更加紧密的能源安全共同体,然而在双方投资与合作过程中诸多相关法律问题也不断涌现,使中国对中亚地区的能源投资风险加大。文章对中亚能源投资中对投资的界定、投资准入、政治风险及环境保护等相关投资法律问题进行研究与分析,提出中国在中亚投资与合作过程中的相应对策,将对中国能源投资规避风险、保护投资利益大有裨益。     

我国居民文化消费影响因素探析

运用我国1983—2012年的数据,通过实证分析考察了可支配收入、教育水平、金融发展和政府文化事业支出对我国居民文化消费的影响。长期均衡分析结果表明,教育水平和金融发展对我国居民文化消费具有显著的促进作用;教育水平提高1%,居民文化消费增加0.454%;金融机构信贷提高1%,居民文化消费增加0.363%;可支配收入和政府文化事业支出对居民文化消费的影响不显著。脉冲响应分析结果表明,可支配收入冲击对居民文化消费的影响在短期由正向转为负向,教育水平冲击和金融发展冲击对居民文化消费短期具有正向影响,政府文化事业支出冲击对居民文化消费短期具有负面影响。根据实证分析的结论,文章提出了扩大我国居民文化消费的政策建议。     

Subgroup Analysis with Time‐to‐Event Data Under a Logistic‐Cox Mixture Model

Subgroup detection has received increasing attention recently in different fields such as clinical trials, public management and market segmentation analysis. In these fields, people often face time‐to‐event data, which are commonly subject to right censoring. This paper proposes a semiparametric Logistic‐Cox mixture model for subgroup analysis when the interested outcome is event time with right censoring. The proposed method mainly consists of a likelihood ratio‐based testing procedure for testing the existence of subgroups. The expectation–maximization iteration is applied to improve the testing power, and a model‐based bootstrap approach is developed to implement the testing procedure. When there exist subgroups, one can also use the proposed model to estimate the subgroup effect and construct predictive scores for the subgroup membership. The large sample properties of the proposed method are studied. The finite sample performance of the proposed method is assessed by simulation studies. A real data example is also provided for illustration.     

Testing Overdispersion in CUBE Models

A practical problem with large-scale survey data is the possible presence of overdispersion. It occurs when the data display more variability than is predicted by the variance–mean relationship. This article describes a probability distribution generated by a mixture of discrete random variables to capture uncertainty, feeling, and overdispersion. Specifically, several tests for detecting overdispersion will be implemented on the basis of the asymptotic theory for maximum likelihood estimators. We discuss the results of a simulation experiment concerning log-likelihood ratio, Wald, Score, and Profile tests. Finally, some real datasets are analyzed to illustrate the previous results.     

Intraday Serial Correlation,Volatility, and Jump: Evidence from China's Stock Market

In this article, we investigate the relationships among intraday serial correlation, jump-robust volatility, positive and negative jumps based on Shanghai composite index high frequency data. We implement variance ratio test to quantify intraday serial correlation. We also measure the continuous part of realized volatility using jump-robust MedRV estimator and disentangle positive and negative jumps using Realized Downside Risk Measure and Realized Upside Potential Measure proposed by Bi et al., (2013 Bi, T., Zhang, B., Wu, H. (2013). Measuring downside risk using high frequency data–realized downside risk measure. Communications in Statistics–Simulation and Computation 42(4):741–754.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]). We find that intraday serial correlation are positively correlated with jump-robust volatility and negatively correlated with negative jumps which confirm the LeBaron effect.     

能效标识对节能产品选择的引导效用分析——基于京东家电线上销售的实证检验

搜集冰箱、洗衣机、空调三种大家电的线上销售数据,通过描述性分析、组间差异比较、多元回归分析等方式分析能效标识的市场引导效果。结果显示消费者对不同等级家电产品的选择量存在差异,但不同能效等级间消费者满意度并无明显差异,能效等级并非是影响消费者选择和满意度的显著因素。