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Likelihood ratio-type tests in weighted composite quantile regression of DTARCH models 被引量:3
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作者 Xiaoqian Liu Xinyuan Song Yong Zhou 《Science China Mathematics》 SCIE CSCD 2019年第12期2571-2590,共20页
The double-threshold autoregressive conditional heteroscedastic(DTARCH) model is a useful tool to measure and forecast the mean and volatility of an asset return in a financial time series. The DTARCH model can handle... The double-threshold autoregressive conditional heteroscedastic(DTARCH) model is a useful tool to measure and forecast the mean and volatility of an asset return in a financial time series. The DTARCH model can handle situations wherein the conditional mean and conditional variance specifications are piecewise linear based on previous information. In practical applications, it is important to check whether the model has a double threshold for the conditional mean and conditional heteroscedastic variance. In this study, we develop a likelihood ratio test based on the estimated residual error for the hypothesis testing of DTARCH models. We first investigate DTARCH models with restrictions on parameters and propose the unrestricted and restricted weighted composite quantile regression(WCQR) estimation for the model parameters. These estimators can be used to construct the likelihood ratio-type test statistic. We establish the asymptotic results of the WCQR estimators and asymptotic distribution of the proposed test statistics. The finite sample performance of the proposed WCQR estimation and the test statistic is shown to be acceptable and promising using simulation studies. We use two real datasets derived from the Shanghai and Shenzhen Composite Indexes to illustrate the methodology. 展开更多
关键词 DTARCH model QUANTILE weigh ted COMPOSITE QUANTILE regression modified LIKELIHOOD ratio test restricted WCQR ESTIMATORS unrestricted WCQR ESTIMATORS
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A new exact p-value approach for testing variance homogeneity
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作者 Juan Wang Xinmin Li Hua Liang 《Statistical Theory and Related Fields》 2022年第1期81-86,共6页
To test variance homogeneity,various likelihood-ratio based tests such as the Bartlett's test have been proposed.The null distributions of these tests were generally derived asymptotically or approximately.We re-e... To test variance homogeneity,various likelihood-ratio based tests such as the Bartlett's test have been proposed.The null distributions of these tests were generally derived asymptotically or approximately.We re-examine the restrictive maximum likelihood ratio(RELR)statistic,and sug-gest a Monte Carlo algorithm to compute its exact null distribution,and so its p-value.It is much easier to implement than most existing methods.Simulation studies indicate that the proposed procedure is also superior to its competitors in terms of type I error and powers.We analyse an environmental dataset for an illustration. 展开更多
关键词 Homogeneity of variances Bartlett’s test restrictive maximum likelihood ratio test type I error rate
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