SHIBOR期限结构的再检验

本文利用结构突变理论重新检验EH假说,发现Campbell和Shiller(1987)模型隐含了有关单一利率的结构突变特征的两个条件：存在共同结构突变点;在共同突变点的突变幅度也完全相同。只有同时满足两个条件,传统EG检验才不会错误拒绝EH假说。本文针对z这些问题改进了实证模型,重点转变为分析EH假说在中国市场不成立的原因,发现排除“利率倒挂”和各利率的共同结构突变点的干扰以后,EH假说分别在SHIBOR长短期利率成立。SHIBOR隔夜拆借利率是一个结构突变的稳定过程。     

Improved nonparametric tolerance intervals based on interpolated and extrapolated order statistics

The standard approach to construct nonparametric tolerance intervals is to use the appropriate order statistics, provided a minimum sample size requirement is met. However, it is well-known that this traditional approach is conservative with respect to the nominal level. One way to improve the coverage probabilities is to use interpolation. However, the extension to the case of two-sided tolerance intervals, as well as for the case when the minimum sample size requirement is not met, have not been studied. In this paper, an approach using linear interpolation is proposed for improving coverage probabilities for the two-sided setting. In the case when the minimum sample size requirement is not met, coverage probabilities are shown to improve by using linear extrapolation. A discussion about the effect on coverage probabilities and expected lengths when transforming the data is also presented. The applicability of this approach is demonstrated using three real data sets.     

Minimum cost linear trend-free 12-run fractional factorial designs

Time trend resistant fractional factorial experiments have often been based on regular fractionated designs where several algorithms exist for sequencing their runs in minimum number of factor-level changes (i.e. minimum cost) such that main effects and/or two-factor interactions are orthogonal to and free from aliasing with the time trend, which may be present in the sequentially generated responses. On the other hand, only one algorithm exists for sequencing runs of the more economical non-regular fractional factorial experiments, namely Angelopoulos et al. [1 P. Angelopoulos, H. Evangelaras, and C. Koukouvinos, Run orders for efficient two-level experimental plans with minimum factor level changes robust to time trends, J. Statist. Plann. Inference 139 (2009), pp. 3718–3724. doi: 10.1016/j.jspi.2009.05.002[Crossref], [Web of Science ®] , [Google Scholar]]. This research studies sequential factorial experimentation under non-regular fractionated designs and constructs a catalog of 8 minimum cost linear trend-free 12-run designs (of resolution III) in 4 up to 11 two-level factors by applying the interactions-main effects assignment technique of Cheng and Jacroux [3 C.S. Cheng and M. Jacroux, The construction of trend-free run orders of two-level factorial designs, J. Amer. Statist. Assoc. 83 (1988), pp. 1152–1158. doi: 10.1080/01621459.1988.10478713[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]] on the standard 12-run Plackett–Burman design, where factor-level changes between runs are minimal and where main effects are orthogonal to the linear time trend. These eight 12-run designs are non-orthogonal but are more economical than the linear trend-free designs of Angelopoulos et al. [1 P. Angelopoulos, H. Evangelaras, and C. Koukouvinos, Run orders for efficient two-level experimental plans with minimum factor level changes robust to time trends, J. Statist. Plann. Inference 139 (2009), pp. 3718–3724. doi: 10.1016/j.jspi.2009.05.002[Crossref], [Web of Science ®] , [Google Scholar]], where they can accommodate larger number of two-level factors in smaller number of experimental runs. These non-regular designs are also more economical than many regular trend-free designs. The following will be provided for each proposed systematic design:

• (1) The run order in minimum number of factor-level changes.

• (2) The total number of factor-level changes between the 12 runs (i.e. the cost).

• (3) The closed-form least-squares contrast estimates for all main effects as well as their closed-form variance–covariance structure.

In addition, combined designs of each of these 8 designs that can be generated by either complete or partial foldover allow for the estimation of two-factor interactions involving one of the factors (i.e. the most influential).     

人民币汇率形成机制改革后的股价和汇率相关性研究

通过协整检定、向量误差修正模型和VEC格兰杰因果检定,使用2005年7月22日~2007年4月27日的日交易数据,实证考察了人民币汇率形成机制改革之后,人民币兑美元汇率与我国国内股价之间的关系。结果发现,人民币兑美元汇率与上证综合指数间存在协整关系,达到了长期均衡;股票价格和汇率间存在着由人民币兑美元汇率到上证综合指数单向的长期和短期因果关系,不存在由上证综合指数到人民币兑美元汇率长期的或者短期的因果关系,人民币兑美元汇率是上证综合指数变化长期的和短期的原因之一。     

Stochastic hydrology: An introduction to wet statistics for dry statisticians

The paper is intended to give non-initiates some idea of the nature of stochastic hydrology. After a brief historical review it concentrates on three recent examples of stochastic modelling procedures that have aroused interest among hydrologists, namely the Hurst Effect, Short-Term Runoff Models, and Stochastic Reservoir Theory.     

New Simple Tests for Panel Cointegration

ABSTRACT

In this paper, two new simple residual-based panel data tests are proposed for the null of no cointegration. The tests are simple because they do not require any correction for the temporal dependencies of the data. Yet they are able to accommodate individual specific short-run dynamics, individual specific intercept and trend terms, and individual specific slope parameters. The limiting distributions of the tests are derived and are shown to be free of nuisance parameters. The Monte Carlo results in this paper suggest that the asymptotic results are borne out well even in very small samples.     

Testing for the Null Hypothesis of Cointegration with a Structural Break

In this paper we propose residual-based tests for the null hypothesis of cointegration with a structural break against the alternative of no cointegration. The Lagrange Multiplier (LM) test is proposed and its limiting distribution is obtained for the case in which the timing of a structural break is known. Then the test statistic is extended to deal with a structural break of unknown timing. The test statistic, a plug-in version of the test statistic for known timing, replaces the true break point by the estimated one. We show the limiting properties of the test statistic under the null as well as the alternative. Critical values are calculated for the tests by simulation methods. Finite-sample simulations show that the empirical size of the test is close to the nominal one unless the regression error is very persistent and that the test rejects the null when no cointegrating relationship with a structural break is present. We provide empirical examples based on the present-value model, the term structure model, and the money-output relationship model.     

中国碳强度影响因素长期均衡与动态分析

选择人均GDP、能源强度、第二产业比重等三个影响因素变量,采用协整理论和误差修正模型分析中国碳强度与三个影响因素变量之间的长期均衡关系,再运用VAR模型的脉冲响应与方差分析等方法分析人均GDP、第二产业比重、能源强度对碳强度的动态影响。研究表明：从长期看,这三个因素对碳强度均产生正影响,其中能源强度对碳强度的影响最大;从动态影响来看,第二产业比重对碳强度影响最明显。因此,降低能源强度和第二产业比重能有效地减少碳强度,特别是调整降低第二产业比重既能提高能源利用率,同时又能减少碳强度。     

我国农村人力资本投资与非农就业关系的实证研究——基于1978-2007年的经验证据

从公共投资、教育、健康、培训及迁移等角度全面度量了我国1978-2007年农村人力资本投资量,并在此基础上运用向量误差修正模型、协整检验、Granger因果检验对我国农村人力资本投资与非农就业的关系做了实证研究。结果表明,人力资本投资量是非农就业总比重的单向Granger原因,即前者有效地促进了后者的提高,但其影响具有滞后性;人力资本投资量不是农村劳动力当地非农就业比重的Granger原因,即前者并未促进后者的提高,反而更有效地促进了农村劳动力向城市非农产业转移。     

中国股价与汇率动态关系的实证分析

通过协整检验、格兰杰因果检验和向量误差修正模型分析自汇率制度改革以来,股价与汇率之间的动态关系。研究发现虽然以上海综合指数和各行业指数为代表的股价与汇率之间都存在负相关关系,但在因果关系检验与协整检验关系中,不同行业指数与汇率之间关系却不同。汇率与上海综合指数、上海商业股指数、上海公共事业股指数和上证综合股指数之间都不存在因果关系,这意味着汇率的变动对这几个变量不产生影响。唯一例外的是上海地产股指数是汇率的格兰杰因果。汇率分别与上证综合指数、上证地产股指数、上证公共事业股指数以及上证综合股指数都存在长期协整关系,而与上证商业股指数之间不存在协整关系。即汇率与这几个变量之间存在长期均衡的趋势,但与上证商业股指数没有长期均衡关系。