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丁岳林 《中学物理教学参考》2008,(11):20-22
在历年的高考物理试题中,实验数据的读取、分析和处理是最基本的问题．《普通高等学校招生全国统一考试物理科考试大纲》关于实验数据及有效数字问题有这样的要求：会记录、处理实验数据,并得出结论;要求知道有效数字的概念,会用有效数字表达直接测量的结果．中学物理实验教学中关于有效数字的知识点,算不上是重点,但却是一难点,或者说得更直接一点, 相似文献
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在环境监测实验中,科学记录实验数据和计算结果,应保留几位数字是根据有效数字的规则来定,不能随便增加或减少位数,对实验数据的记录和处理非常重要．笔者认为：强调有效数字的意义和记录,有利于运用有效数字的运算规则处理数据,从而得到准确的测量结果． 相似文献
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在分析化学实验中，记录实验数据和计算结果应保留几位数字是一件很重要的事，不能随便增加或减少位数．如何培养高校化学专业学生对化学实验数据的正确记录和正确处理的能力呢?笔者认为：强调有效数字的意义及住数，强调有效数字的运算规则，在分析化学实验教学中，注意运用有效数字的运算规则，利于培养高校学生对化学实验数据的正确记录和正确处理的能力． 相似文献
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测量结果的有效数字问题．是物理实验中经常遇到的问题．无论是在直接测量还是在数据处理中,都离不开它．为了帮助学生更好地掌握和运用它．笔者以教学实践为基础,对有效数字的概念、它与测量误差的关系及近似计算等同题谈谈几点浅见。 相似文献
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物理实验中有效数字的确定原则及作用探讨 总被引：1，自引：0，他引：1
从培养科学实验素质的角度出发，明确了有效数字与测量误差之间的内在联系，指出确定有效数字是物理实验课教学的重中之重。给出了新的有效数字实质性定义，并对有效数字读数规则、运算规则进行了实质性解释，归纳了结果有效数字修约的一般原则，阐明了物理实验中有效数字的教学目标。 相似文献
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实验中正确读数的有关问题北京市第一二三中学陶昌宏北京市第三师范学校孙际方一、教学大纲精神全日制中学物理教学大纲规定，在物理实验中要求学生了解误差概念，同时指出：高中要求理解有效数字的意义，测量中能按有效数字的要求读数．根据大纲的精神，近些年高考试题中... 相似文献
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电学实验是离不开有效数字处理的,有效数字的出现和处理是科学实验的重要部分,它是由实验目的和精度所决定的.有效数字的位数是误差理论的讨论范围,一个数的误差的绝对值小于或等于末位数的0.5单位时,该数的全部数字都是有效数字.有效数字的修约规则是“四舍六入五成双”.在加、减、除、乘以及对数的运算中,也是受到有效数字制约的. 相似文献
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本文对二语学习者英语写作表现中的语法复杂度的测量及测量效度进行了实证性研究。为检验测量指标的效度,我们以“中国学习者英语语料库”中的大学英语六级考试作文为样本,检验了T单位、从属小句、非限定动词和衔接成分在测量英语学习者书面语语法复杂度方面的效度。研究表明,上述四个指标能较为有效地反映出测量样本的语法复杂度,其中,T单位、非限定动词和衔接成分对书面语语法复杂度的发展具备预测功能。研究还发现,非限定动词指标在统计检验中优于其他三个指标,而从属小句在测量学习者书面语语法复杂度的发展方面的结果不如其他几项显著。 相似文献
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The Peabody Individual Achievement Test–Revised (PIAT‐R) and Wechsler Individual Achievement Test (WIAT) contain measures of written expression. However, these subtests are not theory‐based and were assessed with inappropriate psychometric analyses. This study attempted to enhance the study of written expression by reexamining the reliability and validity of the PIAT‐R and WIAT Written Expression scoring systems, applying theory and more appropriate statistical analyses. First, items were identified that were the most and least reliable, determined by interrater agreement. Next, the most and least valid items were identified, based on item–total correlations. Subjects included 50 adolescents, men, and women aged 13 to 46 years; raters were three graduate students with experience and training similar to that of the typical test user. Results indicate that seven items were too easy, as virtually all subjects received the maximum score on these items—these items were eliminated. The remaining 24 items were classified as both reliable and valid (9 items), reliable but not valid (4 items), valid with limited reliability (5 items), and neither reliable nor valid (6 items). The WIAT written expression scoring system was found to have more items that were both reliable and valid compared to the PIAT‐R scoring system. Items measuring global, rather than specific, content were also found to be more reliable and valid. © 1999 John Wiley & Sons, Inc. 相似文献
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Are there important aspects of human ability that we have not been measuring? What are the purposes and types of audio that are possible in computerized tests? Will the use of audio in computer‐based tests lead to more valid and reliable measurement? 相似文献
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Robert B. Powell Marc J. Stern Brandon Troy Frensley DeWayne Moore 《Environmental Education Research》2019,25(9):1281-1299
AbstractWhile multiple valid measures exist for assessing outcomes of environmental education (EE) programs, the field lacks a comprehensive and logistically feasible common instrument that can apply across diverse programs. We describe a participatory effort for identifying and developing crosscutting outcomes for Environmental Education in the twenty-first Century (EE21). Following extensive input and debate from a wide range of EE providers and researchers, we developed, tested and statistically validated crosscutting scales for measuring consensus-based outcomes for individual participants in youth EE programs using confirmatory factor analysis across six unique sites, including two single-day field trip locations, four multiday residential programs and one science museum in the United States. The results suggest that the scales are valid and reliable for measuring outcomes that many EE programs in the United States can aspire to influence in adolescent participants, ages 10–14. 相似文献
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利用Agilent LC/MSD TOF建立了快速测定茶叶中4种主要儿茶素的分析方法.首先以儿茶素对应的质谱峰的强度和质谱峰分辨率为基准,采用正交实验设计方法对质谱联用仪的仪器参数进行了优化选择,包括流速,毛细管高压,干燥气体流速及温度,裂解电压,雾化器压力等;依据优化后的质谱测定条件,应用标准加入法,对实际的样品测定进行了重现性、精密度和回收率的考察;最后对实际的茶叶样品的含量进行了测定,该方法单次进样测量时间为2 min,为快速测定茶叶中儿茶素提供了一种可供参考的分析方法. 相似文献
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Curriculum‐Based Measurement silent reading (CBM‐SR) items have been found to be reliable and valid for measuring reading comprehension skills This generalizability study reports the findings from administration of three CBM‐SR passages to fifth through eighth grade students in one school district. Using Repeated Measures Analyses of Variance (RMANOVA) procedures, the statistical probability of performance on the CBM‐SR task as a differential indicator of reading comprehension skill was found to be significant among students in different grade levels and between students who did and did not receive special education services. Follow‐up analyses were conducted using generalizability theory to estimate the amount of variance in CBM‐SR scores from individual score differences, grade levels, and special education status. The results indicated that on two of the passages, variability in CBM‐SR scores came primarily from grade level differences in scores on the tasks, while on the third passage, the differences were most attributable to individual differences in scores, regardless of grade level or special education services. Implications for the use of CBM‐SR items for routine assessment of students' reading skills are discussed. © 2003 Wiley Periodicals, Inc. Psychol Schs 40: 363–377, 2003. 相似文献
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在GR中,引力场各处的时钟快慢不同,引力场中各处的量杆长短不同,但是,引力场中的光速却是不变的.这意味着引力场时空弯曲了,欧几里德几何规律不再成立.其根本原因正是爱因斯坦所开创的广义相对论的几何化纲领. 相似文献
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Previous research has suggested potential advantages for a new type of item for measuring comprehension in reading and listening. The test items are called “chunked” and consist of groups of meaningfully related words in which certain groups have been changed in meaning from the original passage. A chunked type of test, designed to indicate information stored during reading, was developed and analyzed in two studies. The results of Study 1, indicated that the constructed test items were successful in differentiating between readers and nonreaders of the newly composed reading passages. “Using the results of Study I, test items were revised and two forms of a test were produced, complete with standardized instructions. The major purpose of Study 2 was to evaluate the extent to which the revised and standardization test could discriminate between a group of individuals who took the test in its standard form and another group which was given the same amount of time to work on the test items but was not given the benefit of reading the passages. The major result in Study 2 was that individuals who had not read the passages experienced a 75% decrement in their performance on Form A of the Chunked Reading Test as compared to individuals who had read the passages, and for Form B, nonreaders experienced a 78% decrement. From these re- sults, it was concluded that the Chunked Reading Test is a valid test of information storage during reading in terms of its utility in measuring the differences in information stored between readers and nonreaders of passages, and that it offers many advantages over the traditional standardized reading tests. 相似文献
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Research has been focusing increasingly on measuring students’ prior economic knowledge in higher education. However, in German-speaking countries, valid instruments are rare. A diagnostic study investigated the validity and fairness of an internationally established economic knowledge test (adapted German version of TUCE IV and TEL IV) with a representative sample of 7664 students from 46 universities across Germany. Previous findings with the dataset (Zlatkin-Troitschanskaia et al., 2019a) suggest that native language significantly predicts missing answers in the knowledge test. Similar effects can be found for gender. After coding missing answers as incorrect, students with a native language other than German and females are disadvantaged. Using multiple imputation, group differences are still significant but to a lesser extent. This approach is critically discussed in terms of valid diagnostics and assessment in higher education. 相似文献
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William Lee Romine 《International Journal of Science Education》2013,35(17):2872-2891
Efficacy of the Measure of Understanding of Macroevolution (MUM) as a measurement tool has been a point of contention among scholars needing a valid measure for knowledge of macroevolution. We explored the structure and construct validity of the MUM using Rasch methodologies in the context of a general education biology course designed with an emphasis on macroevolution content. The Rasch model was utilized to quantify item- and test-level characteristics, including dimensionality, reliability, and fit with the Rasch model. Contrary to previous work, we found that the MUM provides a valid, reliable, and unidimensional scale for measuring knowledge of macroevolution in introductory non-science majors, and that its psychometric behavior does not exhibit large changes across time. While we found that all items provide productive measurement information, several depart substantially from ideal behavior, warranting a collective effort to improve these items. Suggestions for improving the measurement characteristics of the MUM at the item and test levels are put forward and discussed. 相似文献