A GENERALIZED SIGNED–RANK TEST FOR COMPARISON OF P TREATMENTS

Abstract. Several generalizations of the signed–rank test for testing of equality of p treatments in p related samples against general and trend alternative are discussed. A new generalized test is described and exemplified.     

A System Comparison Approach to Distinguish Two Nonseparable and Nonnested Agricultural Household Models

This study distinguishes two nonseparable agricultural household models for a self-employed farm household. One assumes heterogeneity of farm and nonfarm labor and a competitive market for nonfarm labor. The other assumes homogeneity of the two types of labor and a restricted market for nonfarm labor. We compare demand systems that are derived from them, which have different dependent variables and different numbers of equations. We apply a Cox-type test to compare these complicated nonnested systems. Results show clearly that the former is better for Japanese rice-farming households. Comparison of price elasticities for those models verifies the importance of that test.     

The MOSUM of squares test for monitoring variance changes

In this paper we propose the MOSUM of squares test for monitoring potential variance changes when new observations arrive. It is shown that the limiting distribution of the proposed test is determined by the increments of the Brownian bridge. Finite-sample simulations examine empirical sizes and average detection delays of the proposed test. We apply the proposed test to study how soon a variance change can be detected for the yen/$ exchange rate and the S&P 500 stock index.     

动态货币需求模型：来自中国数据的检验

对动态货币需求模型的实证表明,一年期存款利率的变化对货币需求不产生影响,货币需求只受到前一期GDP平减指数、收入和前一期货币需求的影响。在影响货币需求的三个主要因素中,由于货币需求的惯性较大,前一期货币需求对本期货币需求的影响最大,其次是GDP对本期货币需求的影响,前一期的GDP平减指数对本期的货币需求影响最小,影响程度的弹性差异最大为1.86倍。因此,利率机制在目前的条件下还不能作为调控经济的有效手段。     

Detecting bubbles in Hong Kong residential property market

This study uses a newly developed bubble detection method (Phillips, Shi, and Yu, 2011) to identify real estate bubbles in the Hong Kong residential property market. Our empirical results reveal several positive bubbles in the Hong Kong residential property market, including one in 1995, a stronger one in 1997, yet another one in 2004, and a more recent one in 2008. In addition, the method identifies two negative bubbles in the data, one in 2000 and the other one in 2001. These empirical results continue to be valid for the mass segment and the luxury segment. However, this method has also found a bubble in early 2011 in the overall market, and in the mass segment but not in the luxury segment. This result suggests that the bubble in early 2011 in the Hong Kong real estate market was caused primarily by the mass segment under the demand pressure from end-users of small-to-medium sized apartments.     

我国跨国公司汇率风险的运营性对冲实证分析

本文首先回顾30多年来跨国公司管理汇率风险的运营性对冲战略的发展。在此基础上，用数个指标将这些战略量化，构建了这些指标对汇率风险的影响的模型，并选取我国具有代表性的194个公司作为样本，分析了运营性对冲的绩效。最后，对于我国跨国公司的运营性对冲战略提出了相关的政策建议。     

Tests for zero inflation in a bivariate zero‐inflated Poisson model

The score test statistics for testing zero inflation and covariance parameter are proposed in the bivariate zero‐inflated Poisson (BZIP) regression model. The Monte Carlo studies show that the score test and likelihood ratio test for testing zero inflation underestimate the nominal significance level, while the score test for covariance parameter keeps the significance level close to the nominal one. To overcome this nominal level underestimation, we propose a bootstrap method of the score test for the testing problem of zero inflation. An empirical example with covariates is provided to illustrate the results. In addition, score test for zero inflation is also proposed in the BZIP model, which allows a flexible dependence structure using copula.     

Relative Efficiency of the Fuzzy p-Value Approach to Hypothesis Testing

In missing data problems, it is often the case that there is a natural test statistic for testing a statistical hypothesis had all the data been observed. A fuzzy  p -value approach to hypothesis testing has recently been proposed which is implemented by imputing the missing values in the "complete data" test statistic by values simulated from the conditional null distribution given the observed data. We argue that imputing data in this way will inevitably lead to loss in power. For the case of scalar parameter, we show that the asymptotic efficiency of the score test based on the imputed "complete data" relative to the score test based on the observed data is given by the ratio of the observed data information to the complete data information. Three examples involving probit regression, normal random effects model, and unidentified paired data are used for illustration. For testing linkage disequilibrium based on pooled genotype data, simulation results show that the imputed Neyman Pearson and Fisher exact tests are less powerful than a Wald-type test based on the observed data maximum likelihood estimator. In conclusion, we caution against the routine use of the fuzzy  p -value approach in latent variable or missing data problems and suggest some viable alternatives.     

经济增长和制度性变革对税收收入影响的分析

利用1978~2006年的年度数据,建立时序模型考察了税收与经济增长之间的均衡关系,并利用结构突变理论对税收数据的生成过程进行了分析。指出,税收收入与经济增长具有长期均衡关系,但GDP的变动不能显著解释税收收入的短期波动,而制度性因素尤其是税务机关的征管技术变革对税收收入的短期波动具有显著的解释作用。     

三波形梁钢护栏连接过渡段的有限元仿真模拟试验

文章从高速公路交通事故的统计资料分析了现有半刚性与刚性护栏连接过渡段存在的问题，利用有限元方法对汽车高速碰撞护栏连接过渡段进行仿真模拟试验，提出全新的护栏过渡段设计方法。