Mobiles and Cancer: A Case of Phony Connections?     

Eric D Nordmoe 《Teaching Statistics》2007,29(1):2-7

Students learning statistics want to know how our methods are used in the real world. In response, this article offers a discussion of a relevant and timely medical study reported in recent headlines. Careful consideration of the study raises some ideas to get students engaged with statistics.  相似文献   

A Simple Model to Determine the Efficient Duration of Exams     

Jules L. Ellis 《Educational and psychological measurement》2021,81(3):549

This study develops a theoretical model for the costs of an exam as a function of its duration. Two kind of costs are distinguished: (1) the costs of measurement errors and (2) the costs of the measurement. Both costs are expressed in time of the student. Based on a classical test theory model, enriched with assumptions on the context, the costs of the exam can be expressed as a function of various parameters, including the duration of the exam. It is shown that these costs can be minimized in time. Applied in a real example with reliability .80, the outcome is that the optimal exam time would be much shorter and would have reliability .675. The consequences of the model are investigated and discussed. One of the consequences is that optimal exam duration depends on the study load of the course, all other things being equal. It is argued that it is worthwhile to investigate empirically how much time students spend on preparing for resits. Six variants of the model are distinguished, which differ in their weights of the errors and in the way grades affect how much time students study for the resit.  相似文献   

细长轴车削动特性的研究   总被引：9，自引：0，他引：9  

黄跃华  张景勘  李德滋 《科技通报》2001,17(4):41-45,49

对细长轴车削的动特性进行了分析、试验和研究，为保证细长轴车削的稳定性以提高加工质量，提出了转速与进量的合理计算公式，计算与实验结果基本一致。  相似文献   

品牌生态位测度及其评价方法研究   总被引：17，自引：0，他引：17  

王兴元 《预测》2006,25(5):60-64,80

借鉴生态学原理，对品牌生态位的涵义进行了初探，建立了品牌生态位宽度及重叠度的计算公式，提出了品牌生态位适合度评价的函数法、模糊评价法、适合度复合系数法以及基于同类标杆案例品牌贴近度的品牌生态位适合度评价模型。给出了一个实际应用案例，针对案例中的四个品牌，分别计算了目标品牌、竞争品牌以及标杆品牌的品牌生态位宽度、重叠度。利用综合评价模型对该目标品牌的适合度进行了分析与评价。  相似文献   

二次成像法凸透镜移动距离的研究与应用     

许建国  杜珊  黄鉴 《保山师专学报》2011,30(5):52-54

二次成像法中凸透镜的移动距离是一个重要的参数,分析凸透镜的移动距离与相关变量之间的关系,并举例说明了它的应用。  相似文献   

中国学习者英语语调单位特征研究——一项基于英语专业四级口语考试的研究     

戴峥峥  邵旖一 《南昌教育学院学报》2011,26(2):165-166

本研究采用某高等院校全国英语专业四级口语考试中的第一项（复述故事）任务作为研究对象语料,借助语音分析软件Praat对预料进行筛选、标注、分析,从而发现研究对象的独立语调单位特征主要表现在：用词量少,时长短;语调单位与句法结构的切分存在偏差;多个重读音节并存;调核音调单一,多降少升。  相似文献   

浅谈网页制作技术及其在图书馆的应用     

丁志鹰 《齐齐哈尔师范高等专科学校学报》2003,22(3):109-110

本主要讲述了网页(站)制作的相关知识，以及图书馆进行网页制作的粗浅过程．  相似文献   

功能动作模式下短跑训练实证研究     

冯坤  张建华  邢铎 《搏击·武术科学》2015,(4):102-104

功能动作训练用于短跑中,在于优化短跑运动员的技术动作,预防运动损伤,提高核心力量和核心稳定性。文章运用文献资料法、实验法、数理统计法等研究方法,对西北师范大学体育教育专业田径专选组学生短跑技术进行了研究。结果表明：（1）经过为期三个月的教学实验,实验组和对照组的步幅、步频、100米成绩与实验前相比都有明显的提高（p<0.05）。且实验组高于对照组。（2）功能动作训练能有效的提高短跑运动员的核心力量和核心稳定性。  相似文献   

Effects of forward trunk lean on hamstring muscle kinematics during sprinting     

Ayako Higashihara  Yasuharu Nagano  Kazumasa Takahashi  Toru Fukubayashi 《Journal of sports sciences》2015,33(13):1366-1375

This study aimed to investigate the effects of forward trunk lean on hamstring muscle kinematics during sprinting. Eight male sprinters performed maximal-effort sprints in two trunk positions: forward lean and upright. A three-dimensional musculoskeletal model was used to compute the musculotendon lengths and velocity of the biceps femoris long head, semitendinosus, and semimembranosus muscles during the sprinting gait cycle. The musculotendon lengths of all the three hamstring muscles at foot strike and toe-off were significantly greater during the forward trunk lean sprint than during the upright trunk sprint. In addition, a positive peak musculotendon lengthening velocity was observed in the biceps femoris long head and semimembranosus muscles during the late stance phase, and musculotendon lengths at that instant were significantly greater during the forward trunk lean sprint than during the upright trunk sprint. The present study provides significant evidence that a potential for hamstring muscle strain injury involving forward trunk lean sprinting would exist during the stance phase. The results also indicate that the biceps femoris long head and semimembranosus muscles are stretched during forward trunk lean sprinting while contracting eccentrically in the late stance phase; thus, the elongation load on these muscles could be increased.  相似文献   

诺贝尔科学奖跨学科师承效应定量研究     

门伟莉  张志强 《科学学研究》2015,33(4):498-506

交叉学科往往是学科新的生长点,有可能产生新的科学突破,为科学带来革命性的发展。交叉科学的发展离不开大量跨学科的人才,而高水平跨学科人才的培养始于交叉学科的研究生教育。文章选取1901-2013年诺贝尔科学奖获奖者为研究对象,以是否师从诺贝尔奖得主为分组变量,从物理、化学和生理或医学三大学科内和跨学科角度对比分析师承效应的影响,凸显跨学科师承效应的作用。研究结果表明,与单纯的学科内师承效应相比,考虑跨学科师生关系的师承效应可更显著地促进未来诺贝尔科学奖获奖者的成长和成才。  相似文献