共查询到20条相似文献，搜索用时 125 毫秒
1.
n次独立重复试验的特征是:(1)试验的次数不止一次,而是多次,即次数n≥2;(2)每次试验的条件是一样的,同一试验结果可以发生k(0≤k≤n)次;(3)各次试验之间是相互独立的,试验的结果互不影响,各次试验中同一结果发生的概率相同;(4)每次试验都只有(考虑)事件A发生或事件A不发生两种结果.识别n次独立重复试验模型的关键词是独立、重 相似文献
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林向宇 《佳木斯教育学院学报》2013,(1)
土木工程中,一项关键的试验项目就是击实试验,对击实试验的结果产生影响的主要因素包含土样、含水量及余土高度等,本文主要对这几个影响试验结果的因素进行分析。同时,通过试验结果,对比分析不同土样导致的试验结果差异,对实际室内温度下的含水量与理论含水量的关系进行分析,并对余土高度控制的方法进行论述。 相似文献
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李瑛华 《数学爱好者(高二版)》2008,(4)
古典概型所研究的是最简单的随机试验问题.这种随机试验问题有如下三个特征:(1)试验的结果只有有限个,且每个结果发生的可能性相等;(2)试验的各种结果彼此间互斥;(3)试验的各种结果发生的可能性(即概率)之和等于1. 相似文献
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根据单相变压器空载试验、短路试验与试验表计的特点,从理论上分析了电压表、电流表和功率表的相对位置对试验结果的影响,并依据分析结果设计3种不同接法的试验电路,然后利用简化的电路模型推导出3种不同试验电路所测试验数据的准确性,最后通过试验数据的验证,得出单相变压器空载试验和短路试验表计的正确接法. 相似文献
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在理论分析与现场试验的基础上,介绍了220kV金属氧化物避雷器不拆除一次高压引线试验的方法,通过对常规试验和不拆线试验方法结果的比较,对不拆除一次高压引线试验方法的结果进行了误差分析,得出不拆线试验方法是有效可行的结论. 相似文献
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利用《超级画板》的函数功能和数据迭代功能模拟概率试验,可以克服实物试验次数不可能足够多,试验过程重复枯燥,不能保证试验的随机性等缺点,而且简便易行.其关键在于如何用函数功能将试验结果转化为0和1两个数值,并利用数据迭代功能自动统计试验结果. 相似文献
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邓小平的试验观的认识论特征为 :一方面 ,从认识的三要素看 ,试验认识的主体更具有自主性、能动性、创造性 ;试验认识的客体是全新的、未知的客体 ;试验认识的中介包括的范围更广、更全面。另一方面 ,从试验的过程和结果看 ,试验的过程更具探索性、开创性和风险性 ;试验的结果更具独创性。试验的这些特点揭示了它的认识论特征就是创造认识论 相似文献
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苏教版高中数学教材提到的n次独立重复试验是指：由n次试验构成,且每次试验相互独立完成,每次试验的结果仅有两种对立的状态,即A与A,每次试验中P（A）=p〉0．如何理解这里的“每次试验相互独立完成”？事实上,这里的试验相互独立是指它们每次试验的结果之间是相互独立的,这就涉及到n（n≥2）个随机事件之间的相互独立性． 相似文献
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以2K-H行星齿轮传动系统为研究对象,给出固有频率的计算结果。在此基础上,研究了该系统的频响特性试验,包括试验台的布置及其试验方案的设计;测得系统的频率响应函数和固有频率,并将试验结果与理论计算结果进行了对比分析。 相似文献
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测试元模型在模型驱动的测试中居于核心地位,在测试过程中保证测试元模型能够被正确地存储与读取是非常重要的。借助于JUnit这一通用测试框架,对测试元模型的存储与读取功能进行了单元测试。在明确测试需求的基础上,提出了测试用例的设计方法与测试结果的判定原则,并结合实例进行了说明。最后讨论了测试的具体实现和相应的测试结果。 相似文献
12.
彭立 《湖南第一师范学报》2006,6(1):126-128
现代软件测试理论和实践证明,软件测试不再只是软件开发中的一个阶段,而是自成为一个系统,与软件开发同步进行。软件测试由制订测试计划、测试设计、实施测试、执行测试和评估测试这五个部分构成,每个部分都有其目的和任务,它们依次进行,协同作用,确保了整个软件测试的有序进行。 相似文献
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测前培训可以使应试人熟悉测试内容、测试要求、测试程序和测试纪律 ,有助于提高应试人普通话水平 ,是提高普通话水平测试成绩的重要环节 相似文献
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为更好配合最新研制的重卡轮毂轴承试验机进行相关试验,针对集成化重卡轮毂轴承单元的结构特点,研制一款与试验机主轴和集成化重卡轮毂轴承单元相匹配的试验单元.通过对试验单元相关结构进行分析,并在试验单元上增加轴承内部温度采集传感器的设计,最后通过匹配进行耐久性试验.结果显示,该匹配试验单元能够准确采集到试验轴承的内部温度,具有可靠性和可行性,可应用于实际集成化重卡轮毂轴承单元的试验检测. 相似文献
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高中信息技术学业水平合格性考试作为标准参照性考试,命题过程需要按照考试目标及要求做好难度控制,通过准确预估试题难度控制试卷难度,实现考试结果与考试目标的一致。命题难度控制技术包括试题的难度预估、试卷难度的控制。通过确定影响难度的主要客观因素、设计简便易行的试题难度计算方法、建立试题难度预估的参照模型等三个环节探究试题难度预估的方法,结合实例进一步探究试卷难度的控制技术。 相似文献
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针对大量网络协议存在种种安全漏洞,采用Fuzzy测试可以有效地进行漏洞挖掘.为了提高Fuzzy测试的效率和漏洞挖掘的成功率,设计了启发式的Fuzzy测试方法.通过对待测协议的形式化描述,抽取出协议工作过程.通过对状态转移图的分析以及Fuzzy测试的响应,智能地触发新的测试数据,提高了Fuzzy测试效率.通过对自行设计的样本协议以及两个公开协议漏洞进行测试,漏洞挖掘时间比穷举式的平均缩短了57.3%. 相似文献
18.
Joni M. Lakin 《Educational Assessment》2013,18(1):17-34
The purpose of test directions is to familiarize examinees with a test so that they respond to items in the manner intended. However, changes in educational measurement as well as the U.S. student population present new challenges to test directions and increase the impact that differential familiarity could have on the validity of test score interpretations. This article reviews the literature on best practices for the development of test directions as well as documenting differences in test familiarity for culturally and linguistically diverse students that could be addressed with test directions and practice. The literature indicates that choice of practice items and feedback are critical in the design of test directions and that more extensive practice opportunities may be required to reduce group differences in test familiarity. As increasingly complex and rich item formats are introduced in next-generation assessments, test directions become a critical part of test design and validity. 相似文献
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《Contemporary educational psychology》2002,27(2):270-295
A new measure that focused explicitly on the cognitive dimension of test anxiety was introduced and examined for psychometric quality as compared to existing measures of test anxiety. The new scale was found to be a reliable and valid measure of cognitive test anxiety. The impact of cognitive test anxiety as well as emotionality and test procrastination were subsequently evaluated on three course exams and students' self-reported performance on the Scholastic Aptitude Test for 168 undergraduate students. Higher levels of cognitive test anxiety were associated with significantly lower test scores on each of the three course examinations. High levels of cognitive test anxiety also were associated with significantly lower Scholastic Aptitude Test scores. Procrastination, in contrast, was related to performance only on the course final examination. Gender differences in cognitive test anxiety were documented, but those differences were not related to performance on the course exams. Examination of the relation between the emotionality component of test anxiety and performance revealed that moderate levels of physiological arousal generally were associated with higher exam performance. The results were consistent with cognitive appraisal and information processing models of test anxiety and support the conclusion that cognitive test anxiety exerts a significant stable and negative impact on academic performance measures. 相似文献
20.
Güler Yavuz Temel 《Journal of Educational Measurement》2024,61(1):69-98
The purpose of this study was to investigate multidimensional DIF with a simple and nonsimple structure in the context of multidimensional Graded Response Model (MGRM). This study examined and compared the performance of the IRT-LR and Wald test using MML-EM and MHRM estimation approaches with different test factors and test structures in simulation studies and applying real data sets. When the test structure included two dimensions, the IRT-LR (MML-EM) generally performed better than the Wald test and provided higher power rates. If the test included three dimensions, the methods provided similar performance in DIF detection. In contrast to these results, when the number of dimensions in the test was four, MML-EM estimation completely lost precision in estimating the nonuniform DIF, even with large sample sizes. The Wald with MHRM estimation approaches outperformed the Wald test (MML-EM) and IRT-LR (MML-EM). The Wald test had higher power rate and acceptable type I error rates for nonuniform DIF with the MHRM estimation approach.The small and/or unbalanced sample sizes, small DIF magnitudes, unequal ability distributions between groups, number of dimensions, estimation methods and test structure were evaluated as important test factors for detecting multidimensional DIF. 相似文献