首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
In the literature very little attention has been given to psychophysical scaling, even though this kind of measurement provides many advantages, such as continuous interval scales, more precision, possibilities for easy replications and therefore for correction of measurement error. Besides all kinds of technical reasons one possible explanation for this lack of attention is that the procedures have always been described as completely different from the commonly used measurement procedures. Also, the tests which have been suggested for the quality of the results were quite different from the commonly used procedures. In this paper it will be shown that psychophysical scaling can be formulated in a congeneric test model, i.e., all the commonly used criteria for the quality of measurement instruments like reliability and validity can be applied in the usual way. An illustration of this will be given. Furthermore it will be shown that psychophysical scales are not ratio scales but that they satisfy the requirements of a (log)interval scale.  相似文献   

2.
The multilevel value added approach to measuring school effectiveness is now widely used. We propose a method to adjust for measurement error to investigate the extent to which this changes school effect estimates. It is applied to longitudinal data collected in the region of Cova da Beira (NUT III) for 1st, 3rd, 5th, 7th and 8th grades. Three different variance component models are considered, depending on the predictor variables included. Assuming measurement error occurs in explanatory and/or response variables, corrections are made for different values of the coefficient of reliability. Moreover, models are fitted under the assumption of either independent or correlated measurement errors.  相似文献   

3.
The objective of this research project was to develop a validated scale to measure Level 5 Leadership using the Collins ( 2005 ) Level 5 attributes. An expert panel reduced the 99 attributes from Collins to 74. The 349 participants evaluated their bosses on a 10‐point semantic differential scale for each attribute. A review of the literature suggested that Level 5 leadership and servant leadership represent the same concept; thus the study used a 10‐item servant leadership scale to check for concurrent validity. Additionally, Collins proposed eight untested questions to determine if individuals qualify as Level 5 leaders. Principal component analysis resulted in two factors that explained 55.2% of the variance; these factors matched Collins's proposed personal humility and professional will constructs. The final instrument contains five attributes of personal humility and five attributes of professional will that yield Cronbach alphas of .83 and .83, respectively. The analysis also revealed statistically significant positive relationships between the Level 5 attributes, servant leadership, and a single factor that represented Collins's eight questions.  相似文献   

4.
无形会计数据信度即度量结果的重复性程度,是反映会计数据的客观性指标。效度是判断度量结果即研究对象结果的有效性程度。会计数据的信度与效度的探讨有助于会计信息质量的改善与质量标准的制定,对于进一步展开会计科学的研究也具有一定的意义。本文通过分析会计数据信度与效度的特征性,探讨与验证会计数据信度与效度路径研究方法。  相似文献   

5.
An estimation procedure will be presented for a class of threshold models for ordinal data. These models may include both fixed and random effects with associated components of variance on an underlying scale. The residual error distribution on the underlying scale may be rendered greater flexibility by introducing additional shape parameters, e.g. a kurtosis parameter or parameters to model heterogeneous residual variances as a function of factors and covariates. The estimation procedure is an extension of an iterative re-weighted restricted maximum likelihood procedure, originally developed for generalized linear mixed models. This procedure will be illustrated with a practical problem involving damage to potato tubers and with data from animal breeding and medical research from the literature.  相似文献   

6.
Statistical modelling of school effectiveness in educational research is considered. Variance component models are generally accepted for the analysis of such studies. A shortcoming is that outcome variables are still treated as measured without an error. Unreliable variables produce biases in the estimates of the other model parameters. The variability of the relationships across schools and the effects of schools on students' outcomes differ substantially when taking the measurement error in the dependent variables of the variance component models into account. The random effects model can be extended to handle measurement error using a response model, leading to a random effects item response theory model. This extended random effects model is in particular suitable when subjects are measured repeatedly on the same outcome at several points in time.  相似文献   

7.
Yu  Sen-Chi  Wu  Berlin 《Quality and Quantity》2009,43(3):381-390
The aim of this study is to propose an new approach, fuzzy item response model (FIRM), which combines item response theory (IRT) and fuzzy set theory, in the educational or psychological measurement. Applying FIRM to improve the predictive validity of psychological measurement is verified. We set up a detailed procedure for the FIRM and apply it to a valuable empirical study with Beck Depression Inventory-II (Chinese version) administrated on outpatient diagnosed as depression was given. The results showed the correct classification of depression based on FIRM scoring was 80.3% while that of raw score was only 73.2%. That is, via FIRM scoring, 7.9% of the erroneous judgments of depression inferred from self-reported inventory were reduced. It is also suggested that considerable cost concerning prevention and cure of depression might be reduced via FIRM.  相似文献   

8.
This paper establishes the asymptotic distributions of the impulse response functions in panel vector autoregressions with a fixed time dimension. It also proves the asymptotic validity of a bootstrap approximation to their sampling distributions. The autoregressive parameters are estimated using the GMM estimators based on the first differenced equations and the error variance is estimated using an extended analysis-of-variance type estimator. Contrary to the time series setting, we find that the GMM estimator of the autoregressive coefficients is not asymptotically independent of the error variance estimator. The asymptotic dependence calls for variance correction for the orthogonalized impulse response functions. Simulation results show that the variance correction improves the coverage accuracy of both the asymptotic confidence band and the studentized bootstrap confidence band for the orthogonalized impulse response functions.  相似文献   

9.
By closely examining the examples provided in Nielsen (2003), this paper further explores the relationship between self-efficiency (Meng, 1994) and the validity of Rubin's multiple imputation (RMI) variance combining rule. The RMI variance combining rule is based on the common assumption/intuition that the efficiency of our estimators decreases when we have less data. However, there are estimation procedures that will do the opposite, that is, they can produce more efficient estimators with less data. Self-efficiency is a theoretical formulation for excluding such procedures. When a user, typically unaware of the hidden self-inefficiency of his choice, adopts a self-inefficient complete-data estimation procedure to conduct an RMI inference, the theoretical validity of his inference becomes a complex issue, as we demonstrate. We also propose a diagnostic tool for assessing potential self-inefficiency and the bias in the RMI variance estimator, at the outset of RMI inference, by constructing a convenient proxy to the RMI point estimator.  相似文献   

10.
Dr. R. M. Sakia 《Metrika》1990,37(1):345-351
Summary After a Box-Cox transformation to data following a linear balanced mixed ANOVA model, final results may be presented after retransformation to the original scale of measurement. Consequently, estimation of means which may be unbiased in the transformed scale will not be so after retransformation. In this article, the bias introduced together with the corresponding variance is assessed. It is found that whereas bias may not be a serious problem, the variances are inflated for positive transformation parameter the closer it is to zero.  相似文献   

11.
In this paper, we discuss the properties of preliminary test estimators (PTE) of the parameters of simple linear model with measurement error (ME model) when the slope of the linear model is suspected to be zero. Expressions of the bias, MSE and efficiencies are obtained under conditional as well as unconditional situations with known reliability coefficient. Conditional model results are compared to the standard model without measurement error. We also provide the unconditional model analysis in finite samples. Asymptotic theory under local alternatives is developed when the variance of measurement error or the ratio of the variance of the model error relative to the variance of the measurement error is known. Asymptotic expressions of bias and MSE of the estimators along with their efficiencies are obtained. In every case, it is shown that the measurement error tend to increase the variability of the estimators compared to the estimators without measurement error. Graphs and tables are provided to see these results and to determine optimum level of significance for minimum guaranteed efficiency. Received October 2001 RID="*" ID="*"  A. K. Md. E. Saleh is a Distinguished Research Professor and H. M. Kim is a Ph.D. candidate in the School of Mathematics and Statistics, Carleton University, Ottawa. Acknowledgment. The authors gratefully acknowledge the constructive suggestion of the referees to improve the paper. The research is supported by NSERC grant A3088.  相似文献   

12.
In the context where one main regressor is measured with error and at least one instrumental variable is available for the correction of measurement error, this paper provides, to the best of our knowledge, a first point‐identification result on the variance of measurement error, the variance of latent variable, and their covariance. We show that the parameters are identified if the regression model is not de facto linear. We illustrate the method in an application to identify mean‐reverting measurement error, a typical issue in reported income where the measurement error of income is negatively correlated with the true income.  相似文献   

13.
王继顺  王传斌 《物流科技》2010,33(10):37-41
利用自适应过滤预测法对连云港港口2008年前几个月货物吞吐量数据建立港口吞吐量预测模型,通过VBA编程实现Excel的宏按钮操作,按照预测误差方差最小原则交互实现迭代功能,选择对最小预测误差方差贡献最小的一期对应的权值作为最佳权值进行预测,获得了精确度较高的预测结果。  相似文献   

14.
《Journal of econometrics》2002,111(2):169-194
The impact of response measurement error in duration data is investigated using small parameter asymptotic approximations and compared with the effect of hazard function heterogeneity. The approximations lead to a specification test to detect measurement error which is shown to be related to the class of Information Matrix tests. It is shown that in a commonly used class of models the test statistic is exactly pivotal. The second order asymptotic properties of the alternative forms of the test statistic are derived and the quality of the approximations and the performance of the test are investigated via Monte Carlo experimentation.  相似文献   

15.
Shayle R. Searle 《Metrika》1995,42(1):215-230
Variance components estimation originated with estimating error variance in analysis of variance by equating error mean square to its expected value. This equating procedure was then extended to random effects models, first for balanced data (for which minimum variance properties were subsequently established) and later for unbalanced data. Unfortunately, this ANOVA methodology yields no optimum properties (other than unbiasedness) for estimation from unbalanced data. Today it is being replaced by maximum likelihood (ML) and restricted maximum likelihood (REML) based on normality assumptions and involving nonlinear equations that have to be solved numerically. There is also minimum norm quadratic unbiased estimation (MINQUE) which is closely related to REML but with fewer advantages.An invited paper for the ProbaStat '94 conference, Smolenice, Slovakia, May 30–June 3, 1994 Paper number BU-677 in the Biometrics Unit. Cornell University Ithaca NY  相似文献   

16.
陈立  胡细宝  王瓅琬 《价值工程》2012,31(32):169-172
VaR作为衡量风险的指标,其核心则在于对波动,亦即方差的估计。基于时间序列,关于条件方差的经典模型是GARCH模型,尽管后来又衍生出了EGARCH,PARCH等复杂模型,但在实务中GARCH模型仍占有重要的地位。文章分析了一种比较新的结合了EWMA模型的GARCH模型(以下称为EWMA-GARCH模型)计算VaR的参数估计方法,以检验其在估计波动上的实用性,并对实证检验结果做了理论分析。分析结果表明,尽管该结合模型缺乏完整的理论支持,但是其计算效果仍比较良好,当然这样良好的结果是建立在因缺乏理论依据而导致的对模型的其他要求之上的.至于是采用受理论支持的模型还是并不输实践价值的模型,文章也给出了一定的建议。  相似文献   

17.
Data about personal networks and their characteristics are increasingly used in social science research, especially in research about the quality of life, social support and similar topics (Fischer, 1982; Marsden, 1987; van der Poel, 1993b). Since all data about a persons social network are usually obtained from the respondent himself, the quality of such measurements is a very important issue. Among other factors, the type of social support can affect the quality of social network measurement (Ferligoj and Hlebec, 1998, 1999). Differences in the stability of measurement between the core and extended personal network have also been found (Marsden, 1990; Morgan et al., 1997). The closer and the more important an alter is, the more likely it is that (s)he will be named in any measurement (Hoffmeyer-Zlotnik, 1990; Van Groenou et al., 1990; Morgan et al., 1997). In this paper the results of a recent study on the quality of measurement of tie characteristics in different personal subnetworks are presented. The Multitrait-multimethod (MTMM) approach was used for estimating reliability and validity. A meta analysis of reliability and validity estimates was done by hierarchical clustering. The data were collected in the year 2000 by computer assisted face-to-face and telephone interviews from a random sample of 1033 residents of Ljubljana.  相似文献   

18.
We propose a simple estimator for nonlinear method of moment models with measurement error of the classical type when no additional data, such as validation data or double measurements, are available. We assume that the marginal distributions of the measurement errors are Laplace (double exponential) with zero means and unknown variances and the measurement errors are independent of the latent variables and are independent of each other. Under these assumptions, we derive simple revised moment conditions in terms of the observed variables. They are used to make inference about the model parameters and the variance of the measurement error. The results of this paper show that the distributional assumption on the measurement errors can be used to point identify the parameters of interest. Our estimator is a parametric method of moments estimator that uses the revised moment conditions and hence is simple to compute. Our estimation method is particularly useful in situations where no additional data are available, which is the case in many economic data sets. Simulation study demonstrates good finite sample properties of our proposed estimator. We also examine the performance of the estimator in the case where the error distribution is misspecified.  相似文献   

19.
Summary This paper reviews research situations in medicine, epidemiology and psychiatry, in psychological measurement and testing, and in sample surveys in which the observer(rater or interviewer) can be an important source of measurement error. Moreover, most of the statistical literature in observer variability is surveyed with attention given to a notational unification of the various models proposed. In the continuous data case, the usual analysis of variance (ANOVA) components of variance models are presented with an emphasis on the intraclass correlation coefficient as a measure of reliability. Other modified ANOVA models, response error models in sample surveys, and related multivariate extensions are also discussed. For the categorical data case, special attention is given to measures of agreement and tests of hypotheses when the data consist of dichotomous responses. In addition, similarities between the dichotomous and continous cases are illustrated in terms of intraclass correlation coefficients. Finally, measures of agreement, such as kappa and weighted-kappa, are discussed in the context of nominal and ordinal data. A proposed unifying framework for the categorical data case is given in the form of concluding remarks.  相似文献   

20.
This paper considers the problem of forecasting realized variance measures. These measures are highly persistent estimates of the underlying integrated variance, but are also noisy. Bollerslev, Patton and Quaedvlieg (2016), Journal of Econometrics 192(1), 1–18 exploited this so as to extend the commonly used heterogeneous autoregressive (HAR) by letting the model parameters vary over time depending on the estimated measurement error variances. We propose an alternative specification that allows the autoregressive parameters of HAR models to be driven by a latent Gaussian autoregressive process that may also depend on the estimated measurement error variance. The model parameters are estimated by maximum likelihood using the Kalman filter. Our empirical analysis considers the realized variances of 40 stocks from the S&P 500. Our model based on log variances shows the best overall performance and generates superior forecasts both in terms of a range of different loss functions and for various subsamples of the forecasting period.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号