共查询到19条相似文献，搜索用时 109 毫秒
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本文主要阐述了检测结果的准确度与间接测量的准确度是否相符,利用间接测量中的误差分布与积累来验证检测中测量准确度与仪器配置问题. 相似文献
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在工程技术测量中，对长度、重量、位移等物理量可以直接测量，但也有许多物理量如比重、效率、摩擦系数等不能直接测得．若想确定这类量的大小，必须先测出一些能直接测量的与被测量有直接关系的物理量，然后再按一定的公式计算出所要确定的物理量，这就属于间接测量的任务．如何由直接测量的误差去计算间接测量的值的误差，此即本文所要研究的问题．在问接测量中常有两种情况：一种是已知直接测量值的误差，求间接测量值的误差，或者说是已知自变量误差求函数的误差；另一种是给定间接测量值的误差来确定直接测量值允许的误差．即已知函数… 相似文献
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教学测验是一种间接测量 ,测量必然存在误差。本文阐述了教学测验系统误差与偶然误差产生的原因 ,减小误差的几种方法。 相似文献
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冰的熔解热实验误差传递公式的简化 总被引：1，自引：0，他引：1
王骏 《昆明师范高等专科学校学报》2000,22(4):39-40,45
在冰的熔解热实验中,由于间接测量函数公式的复杂性,致使误差传递公式更加复杂。给计算误差带来了很大的麻烦。若忽略引入误差很小的项,可以简化误差计算,而不会影响其结果。 相似文献
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陈曙东 《数理化学习(高中版)》2008,(9):40-42
物理量的测量无非两种:一是直接测量二是间接测量.对电源电动势和内阻的测量是间接测量的典型实例之一,也是近年来高考的热点.在本实验中,数据处理是重点,误差分析是难点.本文着重谈一谈测定电源电动势和内阻的实验教学中务必重点探究的三个问题. 相似文献
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李宽 《教育前沿(综合版)》2014,(1)
中学物理实验中,常采用间接测量的方法来进行实验。间接测定量的误差由各直接测定量的误差传递而来,误差传递理论具体分析了这一关系。把误差传递理论应用到物理实验中来,指导实验的设计和误差范围的控制,是个值得研究的问题。 相似文献
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平面度误差是被测实际表面对理想平面的变动量,它等于包容实际表面距离为最小的两平行平面间的距离。测量平面度误差的方法有间接测量法,直接测量法及组合测量法等。但以前两种为主。１．间接测量法：测量精度较高,但数据处理繁琐,效率低;２,直接测量法：测量直观,方便,但精度不高;在实践中,参考有关资料,找到一种简捷有效,且精度较高的平面度误差检测及其评定方法。由于在被测平面上通过两块等高垫铁架设的是一根高精度的平尺,通过它检测及其评定平面度误差,既避免了测量误差较大的问题,又提高了测量效率。它可以作为计量室… 相似文献
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In the present studies, we investigated 4- and 5- to 6-year-olds' ability to compare the distances covered by a direct route to a location and an indirect route to the same location. The distances ranged between 16 and 22 feet. The routes were visible from a single vantage point, and objects serving as landmarks were sometimes located along the routes. We found clear demonstrations of the two classic Piagetian distance errors—the direct-indirect error , in which children judge that a direct route and an indirect route cover the same distance, and the interposed object error , in which children judge that a route is shorter when it is segmented by an object located somewhere along the route. The interposed object error occurred because children focused on only one segment of the route, which was consistent with Piaget's explanation of the error. However, in contrast to Piaget, we found that about 40% of 4-year-olds could successfully avoid the direct-indirect error, and in addition, when the routes were visually displayed, they could also avoid the interposed object error. It is important that they also gave correct explanations for why the indirect route was longer, by referring to the fact that it was not straight. For these children at least, the interposed object error was due to difficulty they had representing routes, rather than to a misconception of distance. We suggest that future research should examine whether that may also be true for younger children. 相似文献
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为了验证雁石坪水文站间测方案是否可行,按照《雁石坪水文站巡测方案》的规定,在现有巡测的基础上,对该水文站流量进行间测分析,主要是采用综合水位流量关系曲线对照规范进行误差统计计算分析,论证此方案的可行性。 相似文献
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The efficacy of error correction and various kinds of correction approaches is one of the key issues in second language writing faced by both teachers and researchers. The current paper reviews the definition of error correction and examines the different views on whether error correction in L2 writing should be corrected. In particular, the paper discusses and analyses the three common correction methods: direct correction, peer feedback and indirect correction. Teachers are encouraged to weigh and analyze the advantages and disadvantages of these methods according to the current literature, employ the most beneficial error correction method in L2 writing, and adapt its suitability to their teaching context. 相似文献
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《Structural equation modeling》2013,20(4):459-474
This article establishes a new criterion for the identification of recursive linear models in which some errors are correlated. We show that identification is ensured as long as error correlation does not exist between a cause and its direct effect; no restrictions are imposed on errors associated with indirect causes. 相似文献
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Larry R. Price Daniel P. Gonzalez Tiffany A. Whittaker 《Structural equation modeling》2019,26(1):12-23
A problem central to structural equation modeling is measurement model specification error and its propagation into the structural part of nonrecursive latent variable models. Full-information estimation techniques such as maximum likelihood are consistent when the model is correctly specified and the sample size large enough; however, any misspecification within the model can affect parameter estimates in other parts of the model. The goals of this study included comparing the bias, efficiency, and accuracy of hypothesis tests in nonrecursive latent variable models with indirect and direct feedback loops. We compare the performance of maximum likelihood, two-stage least-squares and Bayesian estimators in nonrecursive latent variable models with indirect and direct feedback loops under various degrees of misspecification in small to moderate sample size conditions. 相似文献
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倪敏 《实验室研究与探索》2006,25(6):645-646,680
许多物理实验,若用传统的实验数据处理方法则存在着计算量大、作图误差大、公式变换复杂、所得结果不直观简洁等诸多问题。现用Visual Basic软件处理棱镜单色仪测定普朗克常数实验数据的主要思想及设计过程,将计算机技术应用于实验数据处理,可迅速、准确地得到实验结果。 相似文献
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Learning from errors is an important way of learning at work. In this article, we analyse conditions under which elder care nurses use errors as a starting point for the engagement in social learning activities (ESLA) in the form of joint reflection with colleagues on potential causes of errors and ways to prevent them in future. The goal of our study was to investigate whether exploratory findings from an earlier study on hospital nurses’ ESLA (Bauer and Mulder Learning in Health and Social Care 6:121–133, 2011) replicate and generalise to the domain of elder care nursing. For this purpose, we surveyed a sample of N?=?180 elder care nurses using vignette-based questionnaires. With these data, we tested a mediation model of nurses’ ESLA suggested by the earlier study. We firstly found a statistically significant indirect effect of error strain on ESLA that is completely mediated by the estimation of an error as relevant for learning (β?=?.16). Secondly, the perception of a safe social team climate at work has a statistically significant indirect effect on ESLA that is completely mediated by nurses’ tendency to cover up errors (β?=?.31). These results entirely cross-validate the exploratory findings of Bauer and Mulder (Learning in Health and Social Care 6:121–133, 2011) on hospital nurses’ ESLA and show that they generalise to the domain of elder care nursing. 相似文献
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钱振纲 《忻州师范学院学报》2002,18(3):13-16
《药》是“双线结构”的说法在学术界和中学语文界至今占着统治地位。实际上这种说法是不科学的。对于《药》的结构的正确理解应当是:小说以老栓为儿子买药治病的经历和结局这一情节的联系性为叙事线索,运用直接描写和间接描写相结合的方法,叙述了华、夏两家有两条基本情节线索贯穿其中的两个相对独立的故事。我们可以称这种结构为“一写二”结构。“一”指的是一条叙事线索,“二”指的是被叙述的两个故事。“双线结构”说中的“双线”指的是“两条故事线索”,《药》只有一条叙事线索的事实在“双线结构”这个概括语中没有得到体现。而不与叙事线索相联系的故事线索属于题材范畴,不属于结构范畴,所以“双线”与“结构”这两个概念在这里联系在一起是犯了逻辑上的错误。 相似文献
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Recent advances in testing mediation have found that certain resampling methods and tests based on the mathematical distribution of 2 normal random variables substantially outperform the traditional z test. However, these studies have primarily focused only on models with a single mediator and 2 component paths. To address this limitation, a simulation was conducted to evaluate these alternative methods in a more complex path model with multiple mediators and indirect paths with 2 and 3 paths. Methods for testing contrasts of 2 effects were evaluated also. The simulation included 1 exogenous independent variable, 3 mediators and 2 outcomes and varied sample size, number of paths in the mediated effects, test used to evaluate effects, effect sizes for each path, and the value of the contrast. Confidence intervals were used to evaluate the power and Type I error rate of each method, and were examined for coverage and bias. The bias-corrected bootstrap had the least biased confidence intervals, greatest power to detect nonzero effects and contrasts, and the most accurate overall Type I error. All tests had less power to detect 3-path effects and more inaccurate Type I error compared to 2-path effects. Confidence intervals were biased for mediated effects, as found in previous studies. Results for contrasts did not vary greatly by test, although resampling approaches had somewhat greater power and might be preferable because of ease of use and flexibility. 相似文献