我国体育彩票销售额的空间异质性及影响因素分析          下载免费PDF全文

王成龙 《河北体育学院学报》2019,33(6):41-48

收集2013—2017年我国31个省份体育彩票销售额的面板数据和2017年各省份社会发展指标的相关数据，运用探索性空间数据分析方法（ESDA），对31个省份体育彩票销售额的空间异质性特征及影响因素进行研究。全局空间自相关分析结果表明，体育彩票销售额具有明显的空间聚集性，且呈显著的空间正相关性。经分析，发现31个省份体育彩票销售额不均衡，东部沿海省份的销售额高于西部省份，提出应重点关注西部地区的体育彩票事业发展。31个省份体育彩票销售呈现出以次冷区域为主，个别热点区域和次热区域相结合的特点，说明我国体育彩票销售的区域性寡占市场特征较明显，提出应加强省份间的沟通交流，促进各区域联动均衡发展。在影响因素方面，人均GDP、体育场地面积对体育彩票销售额具有显著性影响，其中人均GDP对南方的影响大于北方，体育场地面积对东北地区的影响大于西南地区，提出应进一步加大对体育场地建设的投入力度，以促进我国体育彩票事业的发展。  相似文献   

Key somatic variables associated with,and differences between the 4 swimming strokes     

Alan M. Nevill  Yassine Negra  Tony D. Myers  Senda Sammoud  Helmi Chaabene 《Journal of sports sciences》2020,38(7):787-794

ABSTRACT

This study identified key somatic and demographic characteristics that benefit all swimmers and, at the same time, identified further characteristics that benefit only specific swimming strokes. Three hundred sixty-three competitive-level swimmers (male [n = 202]; female [n = 161]) participated in the study. We adopted a multiplicative, allometric regression model to identify the key characteristics associated with 100 m swimming speeds (controlling for age). The model was refined using backward elimination. Characteristics that benefited some but not all strokes were identified by introducing stroke-by-predictor variable interactions. The regression analysis revealed 7 “common” characteristics that benefited all swimmers suggesting that all swimmers benefit from having less body fat, broad shoulders and hips, a greater arm span (but shorter lower arms) and greater forearm girths with smaller relaxed arm girths. The 4 stroke-specific characteristics reveal that backstroke swimmers benefit from longer backs, a finding that can be likened to boats with longer hulls also travel faster through the water. Other stroke-by-predictor variable interactions (taken together) identified that butterfly swimmers are characterized by greater muscularity in the lower legs. These results highlight the importance of considering somatic and demographic characteristics of young swimmers for talent identification purposes (i.e., to ensure that swimmers realize their most appropriate strokes).  相似文献   

Digital Module 16: Longitudinal Data Analysis     

Jeffrey R. Harring  Tessa L. Johnson 《Educational Measurement》2020,39(3):137-138

In this digital ITEMS module, Dr. Jeffrey Harring and Ms. Tessa Johnson introduce the linear mixed effects (LME) model as a flexible general framework for simultaneously modeling continuous repeated measures data with a scientifically defensible function that adequately summarizes both individual change as well as the average response. The module begins with a nontechnical overview of longitudinal data analyses drawing distinctions with cross-sectional analyses in terms of research questions to be addressed. Nuances of longitudinal designs, timing of measurements, and the real possibility of missing data are then discussed. The three interconnected components of the LME model—(1) a model for individual and mean response profiles, (2) a model to characterize the covariation among the time-specific residuals, and (3) a set of models that summarize the extent that individual coefficients vary—are discussed in the context of the set of activities comprising an analysis. Finally, they demonstrate how to estimate the linear mixed effects model within an open-source environment (R). The digital module contains sample R code, diagnostic quiz questions, hands-on activities in R, curated resources, and a glossary.  相似文献   

Associations of neighborhood disorganization and maternal spanking with children’s aggression: A fixed-effects regression analysis     

《Child abuse & neglect》2018

This study employed fixed effects regression that controls for selection bias, omitted variables bias, and all time-invariant aspects of parent and child characteristics to examine the simultaneous associations between neighborhood disorganization, maternal spanking, and aggressive behavior in early childhood using data from the Fragile Families and Child Wellbeing Study (FFCWS). Analysis was based on 2,472 children and their mothers who participated in Wave 3 (2001–2003; child age 3) and Wave 4 (2003–2006; child age 5) of the FFCWS. Results indicated that higher rates of neighborhood crime and violence predicted higher levels of child aggression. Maternal spanking in the past year, whether frequent or infrequent, was also associated with increases in aggressive behavior. This study contributes statistically rigorous evidence that exposure to violence in the neighborhood as well as the family context are predictors of child aggression. We conclude with a discussion for the need for multilevel prevention and intervention approaches that target both community and parenting factors.  相似文献   

Score Reporting for Examinees with Incomplete Data on Large‐Scale Educational Assessments     

Sandip Sinharay 《Educational Measurement》2021,40(1):79-91

Technical difficulties occasionally lead to missing item scores and hence to incomplete data on computerized tests. It is not straightforward to report scores to the examinees whose data are incomplete due to technical difficulties. Such reporting essentially involves imputation of missing scores. In this paper, a simulation study based on data from three educational tests is used to compare the performances of six approaches for imputation of missing scores. One of the approaches, based on data mining, is the first application of its kind to the problem of imputation of missing data. The approach based on data mining and a multiple imputation approach based on chained equations led to the most accurate imputation of missing scores, and hence to most accurate score reporting. A simple approach based on linear regression performed the next best overall. Several recommendations are made regarding the reporting of scores to examinees with incomplete data.  相似文献   

How can we evaluate the effectiveness of grammar schools in England? A regression discontinuity approach     

Binwei Lu 《British Educational Research Journal》2020,46(2):339-363

Previous research evaluating grammar school effectiveness has generally relied on snapshot or longitudinal regression models to deal with pre-existing differences between grammar school pupils and those in non-selective schools. These passive designs are based on correlations, and cannot demonstrate clear positive causal relationships between grammar school attendance and subsequent attainment. After accounting for the variables available for the analysis, pupils in different schools might still have distinct and unmeasured characteristics which threaten the validity of any conclusions drawn. Given that a randomised trial is not feasible under current conditions, this study addresses the limitations of previous research, using a regression discontinuity design (RDD) approach. This is the first use of RDD to attempt to make a robust causal inference about the effectiveness of grammar schools in one local authority in England. However, the authority, the Department for Education and the schools would not provide the individual data on pupils’ 11+ entry test scores, and the scores obtained could not be uniquely matched to Key Stage 4 outcomes. While the model presented suggests that there is an advantage to grammar school attendance, the incomplete data means that the study is more a feasibility trial of this strong design than any kind of definitive test intended to settle the debate on grammar school effectiveness. Conducting this design with national data on grammar school selection would create the most powerful evidence so far. To promote an effective and equitable education system for generations to come, those advocating the expansion of grammar schools should make the responsible decision to disclose all grammar school selection data for the purposes of research.  相似文献   

外部知识源化、知识积累与中国工业绿色增长——动态异质门槛效应研究     

侯建  王刚  陈建成 《科研管理》2020,41(3):91-100

针对开放式创新驱动与绿色发展融合下工业绿色增长路径及动力来源多元化特征，基于中国工业2009-2015省际面板数据，通过考虑非期望产出的Super-SBM模型测算环境和能源约束下的工业绿色增长结构，并采用改进的动态门槛回归模型，从地区知识积累视角系统探究外部知识源化路径驱动工业绿色增长机制的知识积累动态门槛效应及其时空异质性。研究表明：中国工业绿色增长整体水平较低，地区异质性显著；总体上，外部知识源化对工业绿色增长起到了正向作用，但其存在显著的知识积累异质门槛特征：知识积累一旦突破了临界规模，外部知识源化路径驱动工业绿色增长的正向效应则呈现减弱，且知识积累门槛时空分布存在较大差异。  相似文献   

Relative efficiency of R&D activities: A cross-country study accounting for environmental factors in the DEA approach   总被引：1，自引：0，他引：1  

Eric C. Wang  Weichiao Huang 《Research Policy》2007,36(2):260-273

This paper applies the production framework associated with the data envelopment analysis (DEA) method to evaluate the relative efficiency of R&D activities across countries. R&D capital stocks and manpower are treated as inputs while patents and academic publications are considered as outputs. A three-stage approach, which involves using DEA for evaluating efficiency and using Tobit regressions for controlling the external environment, is applied to 30 countries in recent years. The results show that less than one-half of the countries are fully efficient in R&D activities and that more than two-thirds are at the stage of increasing returns to scale. Most countries have a more significant advantage in producing SCI cum EI publications than in generating patents.  相似文献   

基于组合神经网络的聚合物质量预测   总被引：2，自引：0，他引：2  

潘海天  夏陆岳  蔡亦军  李伯耿 《科技通报》2004,20(4):298-302

介绍了一种将组合神经网络用于聚合物质量预测的方法．由定量数据建立的单一神经网络模型往往缺乏泛化能力，而使用组合神经网络模型则可以显著改善模型的泛化能力．由于在建立组合神经网络模型过程中，合适的组合权重对模型是否具有良好预测性能是非常重要的，因此采用了岭回归方法来选择合适的组合权重．所提出的方法已成功应用于PVC颗粒特性的预测研究中。研究结果表明，与单一神经网络模型相比，组合神经网络模型具有更佳的模型预测精度和鲁棒性．  相似文献   

上市公司财务危机预警模型研究   总被引：71，自引：0，他引：71  

姜秀华  任强  孙铮 《预测》2002,21(3):56-61

本文在分析13个变量的基础上,运用Logistic回归给出了判别上市公司财务危机的一个模型。本文模型包括4个变量：毛利率、其它应收款与总资产的比率、短期借款与总资产的比率、股权集中系数;其中的股权集中系数是公司治理结构的直接表征,也是本文模型异于其他预测模型的首要区别。本方模型的回判准确率为84．52％,而对2000年新增加的“ST”公司的判别准确率则达到了95．45％。  相似文献