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1.
Leo M. Harvill 《Educational Measurement》1991,10(2):33-41
The standard error of measurement (SEM) is the standard deviation of errors of measurement that are associated with test scores from a particular group of examinees. When used to calculate confidence bands around obtained test scores, it can be helpful in expressing the unreliability of individual test scores in an understandable way. Score bands can also be used to interpret intraindividual and interindividual score differences. Interpreters should be wary of over-interpretation when using approximations for correctly calculated score bands. It is recommended that SEMs at various score levels be used in calculating score bands rather than a single SEM value. 相似文献
2.
We investigated the statistical properties of the K-index (Holland, 1996) that can be used to detect copying behavior on a test. A simulation study was conducted to investigate the applicability of the K-index for small, medium, and large datasets. Furthermore, the Type I error rate and the detection rate of this index were compared with the copying index, ω (Wollack, 1997). Several approximations were used to calculate the K-index. Results showed that all approximations were able to hold the Type I error rates below the nominal level. Results further showed that using ω resulted in higher detection rates than the K-indices for small and medium sample sizes (100 and 500 simulees). 相似文献
3.
1 Introduction Since the finite element method was proposed ,there has been plenty of work about it (see [1 -4]) .They deeply analyzed and studied the finite elementmethod and gave us the feasibility of it on the theoryside . On the practice side ,the finite element methodhas successfully solved various problems ,especiallyinphysical and engineering fields[5 ,6]. Variational inequalities appear in a variety of nonlin-ear physical models .In particular ,variational inequali-ties have been used… 相似文献
4.
研究具有非凸条件的单个守恒律初边值问题的粘性逼近解的L^1模误差估计．在流函数有一个拐点的条件下,就初始值为两段常数和边界值为常数的情形,根据弱熵解的几何结构,使用匹配行波解方法导出其粘性逼近解和无粘性解间的L^1模误差界为0（ε^1/2＋ε ｜lnε｜）． 相似文献
5.
《Structural equation modeling》2013,20(4):556-574
Approximations to the distributions of goodness-of-fit indexes in structural equation modeling are derived with the assumption of multivariate normality and slight misspecification of models. The fit indexes considered in this article are Joreskog and Sorbom's goodness-of-fit index (GFI) and the adjusted GFI, McDonald's absolute GFI, Steiger and Lind's root mean squared error of approximation, Steiger's Γ1 and Γ2, Bentler and Bonett's normed fit index, Bollen's incremental fit index and ρ1, Tucker and Lewis's index ρ2, and Bentler's fit index (McDonald and Marsh's relative noncentrality index). An approximation to the asymptotic covariance matrix for the fit indexes is derived by using the delta method. Furthermore, approximations to the densities of the fit indexes are obtained from the transformations of the asymptotically noncentral chi-square distributed variable. A simulation is carried out to confirm the accuracy of the approximations. 相似文献
6.
In the nonequivalent groups with anchor test (NEAT) design, the standard error of linear observed‐score equating is commonly estimated by an estimator derived assuming multivariate normality. However, real data are seldom normally distributed, causing this normal estimator to be inconsistent. A general estimator, which does not rely on the normality assumption, would be preferred, because it is asymptotically accurate regardless of the distribution of the data. In this article, an analytical formula for the standard error of linear observed‐score equating, which characterizes the effect of nonnormality, is obtained under elliptical distributions. Using three large‐scale real data sets as the populations, resampling studies are conducted to empirically evaluate the normal and general estimators of the standard error of linear observed‐score equating. The effect of sample size (50, 100, 250, or 500) and equating method (chained linear, Tucker, or Levine observed‐score equating) are examined. Results suggest that the general estimator has smaller bias than the normal estimator in all 36 conditions; it has larger standard error when the sample size is at least 100; and it has smaller root mean squared error in all but one condition. An R program is also provided to facilitate the use of the general estimator. 相似文献
7.
Wendy M. Yen 《Educational Measurement》1988,7(4):16-17
Phillips and Clarizio (1988) make a serious error In concluding that developmental standard score scales produce unrealistic expectations for growth of low-achieving students. The nature of their error is described in this response to their paper. 相似文献
8.
Error indices (bias, standard error of estimation, and root mean squared error) obtained on different measurement scales under different test-termination rules in computerized adaptive testing (CAT) were examined. Four ability estimation methods (maximum likelihood estimation, weighted likelihood estimation, expected a posterior, and maximum a posterior), three measurement scales (θ, number-correct score, and ACT score), and three test-termination rules (fixed length, fixed standard error, and target information) were studied for a real and a generated item pool. The findings indicated that the amount and direction of bias, standard error of estimation, and root mean squared error obtained under different ability estimation methods were influenced both by scale transformations and by test-termination rules in a CAT environment. The implications of these effects for testing programs are discussed. 相似文献
9.
New confidence intervals for the Wechsler Intelligence Scale for Children-Revised (WISC-R) are provided to improve accuracy over existing tables (which center the confidence interval on the child's actual quotient and construct intervals upon the standard error of measurement). These new tables follow Schulte and Borich (1988) in centering confidence intervals on the estimated true IQ and constructing intervals with either the standard error of estimate or the standard error of prediction. The tables are more conservative and reflect more accurate statistical formulas for the construction of WISC-R confidence intervals for WISC-R quotients. 相似文献
10.
陈誌敏 《武汉工程职业技术学院学报》2006,18(2):72-76
在常微分方程的求解问题中，只有少数十分简单的常微分方程能够用初等方法求得它们的解，多数情形只能利用近似方法求解。龙格-库塔法是最常用的一种，因为它相当精确、稳定、容易编程。从理论上导出了截断误差和步长之间的关系，然后在Mathemaica平台上自编运算程序，用数学实验的方法验证了这一结果。 相似文献
11.
P. L. GARDNER 《Journal of Educational Measurement》1970,7(4):271-273
Lord (1959) has shown that the standard error of measurement of a test is, for all practical purposes, directly proportional to the square root of the number of items on the test. More specifically, Lord found empirically that the standard error of a test was equal to . if the reliability of the test was computed by the Kuder-Richardson (KR) 20 formula. If the KR-21 formula was used, the standard error was equal to . . The present paper sets out to show how these relationships may be derived from the defining formulas of reliability and standard error of measurement, if certain simple assumptions about values of test statistics are made. 相似文献
12.
Christian Geiser Michael Eid Stephen G. West Tanja Lischetzke Fridtjof W. Nussbeck 《Structural equation modeling》2013,20(3):409-436
It is well known that measurement error in observable variables induces bias in estimates in standard regression analysis and that structural equation models are a typical solution to this problem. Often, multiple indicator equations are subsumed as part of the structural equation model, allowing for consistent estimation of the relevant regression parameters. In many instances, however, embedding the measurement model into structural equation models is not possible because the model would not be identified. To correct for measurement error one has no other recourse than to provide the exact values of the variances of the measurement error terms of the model, although in practice such variances cannot be ascertained exactly, but only estimated from an independent study. The usual approach so far has been to treat the estimated values of error variances as if they were known exact population values in the subsequent structural equation modeling (SEM) analysis. In this article we show that fixing measurement error variance estimates as if they were true values can make the reported standard errors of the structural parameters of the model smaller than they should be. Inferences about the parameters of interest will be incorrect if the estimated nature of the variances is not taken into account. For general SEM, we derive an explicit expression that provides the terms to be added to the standard errors provided by the standard SEM software that treats the estimated variances as exact population values. Interestingly, we find there is a differential impact of the corrections to be added to the standard errors depending on which parameter of the model is estimated. The theoretical results are illustrated with simulations and also with empirical data on a typical SEM model. 相似文献
13.
基于牛顿前向插值公式,提出一种对任意阶多维函数可实现无差逼近的新型CMAC神经网络———NFI-CMAC,详细阐述了基本原理、插值算法及训练规则。基于NFI-CMAC,提出了一种快速、高精度的控制系统参数在线智能辨识方案,仿真实例表明了该方案的可行性与有效性。 相似文献
14.
David Woodruff 《Journal of Educational Measurement》1990,27(3):191-208
Previous methods for estimating the conditional standard error of measurement (CSEM) at specific score or ability levels are critically discussed, and a brief summary of prior empirical results is given. A new method is developed that avoids theoretical problems inherent in some prior methods, is easy to implement, and estimates not only a quantity analogous to the CSEM at each score but also the conditional standard error of prediction (CSEP) at each score and the conditional true score standard deviation (CTSSD) at each score, The new method differs from previous methods in that previous methods have concentrated on attempting to estimate error variance conditional on a fixed value of true score, whereas the new method considers the variance of observed scores conditional on a fixed value of an observed parallel measurement and decomposes these conditional observed score variances into true and error parts. The new method and several older methods are applied to a variety of tests, and representative results are graphically displayed. The CSEM-Iike estimates produced by the new method are called conditional standard error of measurement in prediction (CSEMP) estimates and are similar to those produced by older methods, but the CSEP estimates produced by the new method offer an alternative interpretation of the accuracy of a test at different scores. Finally, evidence is presented that shows that previous methods can produce dissimilar results and that the shape of the score distribution may influence the way in which the CSEM varies across the score scale. 相似文献
15.
The purpose of this simulation study was to assess the performance of latent variable models that take into account the complex sampling mechanism that often underlies data used in educational, psychological, and other social science research. Analyses were conducted using the multiple indicator multiple cause (MIMIC) model, which is a flexible and effective tool for relating observed and latent variables. The data were simulated in a hierarchical framework (e.g., individuals nested in schools) so that a multilevel modeling approach would be appropriate. Analyses were conducted accounting for and not accounting for the nested data to determine the impact of ignoring such multilevel data structures in full structural equation models. Results highlight the differences in modeling results when the analytic strategy is congruent with the data structure and what occurs when this congruency is absent. Type I error rates and power for the standard and multilevel methods were similar for within-cluster variables and for the multilevel model with between-cluster variables. However, Type I error rates were inflated for the standard approach when modeling between-cluster variables. 相似文献
16.
David Woodruff 《Journal of Educational Measurement》1991,28(3):191-196
In Woodruff (1990), I derived estimates for the conditional standard error of measurement in prediction (CSEMP), the conditional standard error of estimation (CSEE), and the conditional standard error of prediction (CSEP). My original estimates assume that the conditional residual error score variances and the conditional residual true score variances, obtained from the regression of an observed score onto a parallel observed score, obey the same step-up rules as do the marginal error score variance and the marginal true score variance. The present article derives alternative estimates for the various test score conditional variances that do not depend on these assumptions. 相似文献
17.
The goal of the current study was to introduce a new stopping rule for computerized adaptive testing. The predicted standard error reduction stopping rule (PSER) uses the predictive posterior variance to determine the reduction in standard error that would result from the administration of additional items. The performance of the PSER was compared to that of the minimum standard error stopping rule and a modified version of the minimum information stopping rule in a series of simulated adaptive tests, drawn from a number of item pools. Results indicate that the PSER makes efficient use of CAT item pools, administering fewer items when predictive gains in information are small and increasing measurement precision when information is abundant. 相似文献
18.
Andrew C. Dwyer 《Journal of Educational Measurement》2016,53(1):3-22
This study examines the effectiveness of three approaches for maintaining equivalent performance standards across test forms with small samples: (1) common‐item equating, (2) resetting the standard, and (3) rescaling the standard. Rescaling the standard (i.e., applying common‐item equating methodology to standard setting ratings to account for systematic differences between standard setting panels) has received almost no attention in the literature. Identity equating was also examined to provide context. Data from a standard setting form of a large national certification test (N examinees = 4,397; N panelists = 13) were split into content‐equivalent subforms with common items, and resampling methodology was used to investigate the error introduced by each approach. Common‐item equating (circle‐arc and nominal weights mean) was evaluated at samples of size 10, 25, 50, and 100. The standard setting approaches (resetting and rescaling the standard) were evaluated by resampling (N = 8) and by simulating panelists (N = 8, 13, and 20). Results were inconclusive regarding the relative effectiveness of resetting and rescaling the standard. Small‐sample equating, however, consistently produced new form cut scores that were less biased and less prone to random error than new form cut scores based on resetting or rescaling the standard. 相似文献
19.
This Monte Carlo simulation study compares methods to estimate the effects of programs with multiple versions when assignment of individuals to program version is not random. These methods use generalized propensity scores, which are predicted probabilities of receiving a particular level of the treatment conditional on covariates, to remove selection bias. The results indicate that inverse probability of treatment weighting (IPTW) removes the most bias, followed by optimal full matching (OFM), and marginal mean weighting through stratification (MMWTS). The study also compared standard error estimation with Taylor series linearization, bootstrapping and the jackknife across propensity score methods. With IPTW, these standard error estimation methods performed adequately, but standard errors estimates were biased in most conditions with OFM and MMWTS. 相似文献
20.
仝国强 《天津职业院校联合学报》2002,4(4):106-108
利用Excel处理化学中算术平均值、平均偏差、相对平均偏差、标准偏差、相对标准偏差、物质的量浓度、溶液的H+浓度、溶液的pH值、缓冲溶液等一些常见的数据处理和计算问题。 相似文献