Normal theory sample size formulas for some nonnormal distributions

Sample size procedures of T- and F-tests for some nonnormal distributions are discussed. An adaptation to the Kruskal-Wallis and Friedman tests is mentioned.     

Number of Replications Required in Control Chart Monte Carlo Simulation Studies

Monte Carlo simulations have been used extensively in studying the performance of control charts. Researchers have used various numbers of replications in their studies, but almost none of them provided justifications for the number of replications used. Currently, there are no empirically based recommendations regarding the required number of replications to ensure accurate results. This research examined six recently published studies to develop recommendations for the minimum number of replications necessary to reproduce the reported results within a specified degree of accuracy. The results of this study indicated that using 10,000 replications was unnecessarily large and a smaller number of replications could be used to reproduce the target ARLs within the 2% error bands satisfying the modified Mundfrom's criteria. In many cases, only 5,000 replications or fewer were required. In general, the number of replications required to reproduce the target ARL decreased as the shift size increased. In addition, the results of this study provide general recommendations for the required number of replications to use in future SPC simulation studies.     

最低工资政策的城镇家庭收入分配效应研究

家庭在福利分析中具有重要地位，但家庭收入如何受最低工资政策影响却很少得到关注。本文采用2005-2015年中国综合社会调查（CGSS）数据，利用多时期双重差分和再中心化影响函数回归方法实证考察了最低工资政策对我国城镇家庭收入及其分布的影响。研究发现：①最低工资标准上涨显著提升了处于贫困标准1~2倍家庭的收入水平，对贫困标准以下或高于贫困标准2倍以上的家庭收入没有影响；②最低工资标准提升可有效减缓城镇家庭收入不平等，尤其对家庭收入分布较低分位部分的不平等程度有明显改善；③最低工资政策对家庭收入的最终影响取决于工资溢出效应和就业挤出效应的比较，且其对不同收入等级家庭中成员的收入和就业影响存在明显的异质性。政府在制定最低工资政策时，应针对低收入女性劳动力出台相应的配套措施，以保证各类低收入家庭均能从最低工资标准提升中受益。     

Non-parametric estimation of the long-range dependence exponent for Gaussian processes

We consider a class of long-range-dependent Gaussian processes defined in a semiparametric framework. We propose a new estimator of the long-range dependence parameter, based on the integration of the periodogram in two windows. We show that it is asymptotically Gaussian and calculate the rate of convergence. We optimise parameters defining the window function for the minimum mean-square-error criterion. In a Monte-Carlo study, we compare the proposed estimator with previously studied estimators.     

Generalized discrete discrepancy and its applications in experimental designs

In recent years, there has been increasing interest in the study of discrete discrepancy. In this paper, the popular discrete discrepancy is extended to the so-called generalized discrete discrepancy. Connections among generalized discrete discrepancy and other optimality criteria, such as orthogonality, generalized minimum aberration and minimum moment aberration, are investigated. These connections provide strong statistical justification of generalized discrete discrepancy. A lower bound of generalized discrete discrepancy is also obtained, which serves as an important benchmark of design uniformity.     

Optimal split‐plot orthogonal arrays

It is well known that many industrial experiments have split‐plot structures. Compared to completely randomised experiments, split‐plot designs are more economical and thus have received much attention among researchers. Much work has been done for two‐level split‐plot designs. In this article, we consider split‐plot designs with factors of three, more than three, or mixed levels and with both qualitative and quantitative factors. We show that if two designs with both qualitative and quantitative factors are geometrically isomorphic, then their generalised wordlength patterns are identical. Three design scenarios are considered for optimal designs. The corresponding wordlength patterns are defined and the minimum aberration mixed‐level split‐plot designs having 18 and 36 runs are tabulated.     

从收入分配和经济发展的角度看我国的最低工资制度

本文基于我国的一些特殊的国情,从动态的视角出发,讨论了最低工资制度对我国收入分配格局和经济发展的影响.本文研究认为,由于我国特殊的国情,一种合适的最低工资制度在我国可能会产生以下三种效应:第一,最低工资制度具有改善我国收入分配格局,缩小收入差距的功能;第二,一个各地区有差别的最低工资限制可能会促进我国的产业结构向内地转移,促进我国的产业结构升级;第三,长期来看,最低工资限制可能会强制低人力资本工资进行人力资本投资,有助于我国人力资本的提升.     

市场状态依存的套期保值策略研究

最小方差套保策略没有考虑均值信息,没有考虑套保的成本和收益,不能区分买入套保和卖出套保。针对这一缺陷,本文在最小VaR套保策略框架下,提出了市场状态依存的套保策略,以区分买入套保和卖出套保,利用市场状态的信息来改善套保的财务表现。论文首先在理论上比较了市场状态依存策略与最小方差策略的套保比、套保的成本或收益,进一步基于铜期货市场、原油期货市场的数据实证比较了这两种策略的财务表现。理论和实证结果均表明：相对于最小方差套保策略,市场状态依存的买入套保策略的成本更低,卖出套保策略的收益更高;论文最后讨论了此策略的应用范围和局限性。