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1.
基于分组的异方差检验和两阶段估计 总被引:1,自引:0,他引:1
张荷观 《数量经济技术经济研究》2006,23(1):129-137
本文提出了一种基于分组的异方差检验法,并给出了存在异方差时的两阶段估计。 相似文献
2.
We propose two new types of nonparametric tests for investigating multivariate regression functions. The tests are based on cumulative sums coupled with either minimum volume sets or inverse regression ideas; involving no multivariate nonparametric regression estimation. The methods proposed facilitate the investigation for different features such as if a multivariate regression function is (i) constant, (ii) of a bathtub shape, and (iii) in a given parametric form. The inference based on those tests may be further enhanced through associated diagnostic plots. Although the potential use of those ideas is much wider, we focus on the inference for multivariate volatility functions in this paper, i.e. we test for (i) heteroscedasticity, (ii) the so-called ‘smiling effect’, and (iii) some parametric volatility models. The asymptotic behavior of the proposed tests is investigated, and practical feasibility is shown via simulation studies. We further illustrate our methods with real financial data. 相似文献
3.
In this paper, we study a Bayesian approach to flexible modeling of conditional distributions. The approach uses a flexible model for the joint distribution of the dependent and independent variables and then extracts the conditional distributions of interest from the estimated joint distribution. We use a finite mixture of multivariate normals (FMMN) to estimate the joint distribution. The conditional distributions can then be assessed analytically or through simulations. The discrete variables are handled through the use of latent variables. The estimation procedure employs an MCMC algorithm. We provide a characterization of the Kullback–Leibler closure of FMMN and show that the joint and conditional predictive densities implied by the FMMN model are consistent estimators for a large class of data generating processes with continuous and discrete observables. The method can be used as a robust regression model with discrete and continuous dependent and independent variables and as a Bayesian alternative to semi- and non-parametric models such as quantile and kernel regression. In experiments, the method compares favorably with classical nonparametric and alternative Bayesian methods. 相似文献
4.
Since the level of markets’ information efficiency is key to profiteering by strategic players, Shocks; such as the COVID-19 pandemic, can play a role in the nature of markets’ information efficiency. The martingale difference and conditional heteroscedasticity tests are used to evaluate the Adaptive form of market efficiency for four (4) major stock market indexes in the top four affected economies during the COVID-19 pandemic (USA, Brazil, India, and Russia). Generally, based on the martingale difference spectral test, there is no evidence of a substantial change in the levels of market efficiency for the US and Brazilian stock markets in the short, medium, and long term. However, in the long term, the Indian stock markets became more information inefficient after the coronavirus outbreak while the Russian stock markets become more information efficient. Intuitively, these affect the forecastability and predictability of these markets’ prices and/or returns. Thereby, informing the strategic and trading actions of stock investors (including arbitrageurs) towards profit optimization, portfolio asset selection, portfolio asset adjustment, etc. Similar policy implications are further discussed. 相似文献
5.
Under a quantile restriction, randomly censored regression models can be written in terms of conditional moment inequalities. We study the identified features of these moment inequalities with respect to the regression parameters where we allow for covariate dependent censoring, endogenous censoring and endogenous regressors. These inequalities restrict the parameters to a set. We show regular point identification can be achieved under a set of interpretable sufficient conditions. We then provide a simple way to convert conditional moment inequalities into unconditional ones while preserving the informational content. Our method obviates the need for nonparametric estimation, which would require the selection of smoothing parameters and trimming procedures. Without the point identification conditions, our objective function can be used to do inference on the partially identified parameter. Maintaining the point identification conditions, we propose a quantile minimum distance estimator which converges at the parametric rate to the parameter vector of interest, and has an asymptotically normal distribution. A small scale simulation study and an application using drug relapse data demonstrate satisfactory finite sample performance. 相似文献
6.
Joseph G. Eisenhauer 《Empirical Economics》2005,30(2):465-471
A recent study by Cairns and Davis (1998) tested and rejected the Hotelling Valuation Principle (HVP) using cross-sectional data on gold mines. But a replication of that study using the same data suggests the presence of heteroscedastic errors. In contrast to the results of ordinary least squares regressions, robust estimation and weighted least squares results indicate that the HVP may not be rejected at conventional levels of significance. Moreover, the alternative valuation equations proposed by Cairns and Davis can require additional and often unavailable information regarding mineral production. Matched pairs tests indicate that prediction accuracy is roughly comparable across all of the equations examined.Revisions to this paper were completed during a sabbatical at the Life Cycle Institute in the Catholic University of America. I thank Ernest M. Zampelli, Philip Pfaff, two anonymous referees, and the editors for helpful comments. Any errors are my own.First version received: May 2003/Final version received: April 2004 相似文献
7.
Estimation of technical inefficiency effects using panel data and doubly heteroscedastic stochastic production frontiers 总被引:3,自引:0,他引:3
In previous studies, measures of technical inefficiency effects derived from stochastic production frontiers have been estimated
from residuals which are sensitive to specification errors. This study corrects for this inaccuracy by extending the doubly
heteroscedastic stochastic cost frontier suggested by Hadri (1999) to the model for technical inefficiency effects. This model
is a stochastic frontier production function for panel data as proposed by Battese and Coelli (1995). The study uses, for
illustration of the techniques, data on 101 mainly cereal farms in England. We find that the correction for heteroscedasticity
is supported by the data. Both point estimates and confidence intervals for technical efficiencies are provided. The confidence
intervals are constructed by extending the “Battese-Coelli” method reported by Horrace and Schmidt (1996) by allowing the
technical inefficiency to be time varying and the disturbance terms to be heteroscedastic. The confidence intervals reveal
the precision of technical efficiency estimates and show the deficiencies of making inferences based exclusively on point
estimates.
First version received: March 2000/Final version received: Oct. 2001
RID="*"
ID="*" The authors are grateful to the Economic and Social Research Council for access to their Data Archive which has provided
the data for this research. We are indebted to Badi Baltagi and two anonymous referees for their helpful comments and suggestions.
The usual caveat applies. 相似文献
8.
Tiziana Laureti 《International Advances in Economic Research》2008,14(1):76-89
The objective of this paper is to suggest the use of a stochastic frontier model in which the inefficiency component is heteroscedastic
in the measurement of technical efficiency in Human Capital Formation in the Italian University System. The heteroscedastic
frontier model enables one to consider the effect of students’ individual characteristics and the influences of the resources
and organization of the specific faculty on efficiency. The suggested model is applied to the case of Florence University
graduates. The results show that the model specification is strongly supported by the data. Moreover, the suggested specification
explains variation in technical efficiency in terms of graduate-specific factors. The technical efficiency scores obtained
are comparable across faculties.
相似文献
Tiziana LauretiEmail: |
9.
This paper estimates a class of models which satisfy a monotonicity condition on the conditional quantile function of the response variable. This class includes as a special case the monotonic transformation model with the error term satisfying a conditional quantile restriction, thus allowing for very general forms of conditional heteroscedasticity. A two-stage approach is adopted to estimate the relevant parameters. In the first stage the conditional quantile function is estimated nonparametrically by the local polynomial estimator discussed in Chaudhuri (Journal of Multivariate Analysis 39 (1991a) 246–269; Annals of Statistics 19 (1991b) 760–777) and Cavanagh (1996, Preprint). In the second stage, the monotonicity of the quantile function is exploited to estimate the parameters of interest by maximizing a rank-based objective function. The proposed estimator is shown to have desirable asymptotic properties and can then also be used for dimensionality reduction or to estimate the unknown structural function in the context of a transformation model. 相似文献
10.
空间单元大小以及其它的经济特征上的差异,常常会导致空间异方差问题。本文给出了广义空间模型异方差问题的三种不同估计方法。第一种方法是将异方差形式参数化,来克服自由度的不足,使用ML估计进行实现。而针对异方差形式未知时,分别采用了基于2SLS的迭代GMM估计和更加直接的MCMC抽样方法加以解决,特别是MCMC方法表现得更加优美。蒙特卡罗模拟表明,给定异方差形式条件下, ML估计通过异方差参数化的方法依然可以获得较好的估计效果。而异方差形式未知的情况下,另外两种方法随着样本数的增大时也可以与ML的估计结果趋于一致。 相似文献