农业企业总经理变更与经营绩效的相关性分析——基于中国上市公司的实证研究

高管变更是一个有效的公司控制机制。当企业的经营绩效下降时,董事会便有可能更换现任的高管。对中国农业上市企业总经理变更样本进行的实证研究表明,企业的经营绩效可以在相当大的程度上解释总经理变更的可能性。然而,与董事会初衷不一致的是,总经理变更后企业的经营绩效并没有得到明显改善。因此,农业企业董事会在变更总经理的决策过程中需要非常谨慎,尤其是过度或者频繁变更总经理会给企业带来诸多不良影响。     

民族戏剧学研究的深度延伸——评黎羌教授新著《民族戏剧文化大视野》

陕西师范大学文学院黎羌教授是一位长年从事中西戏剧文化比较、中国少数民族戏剧与民族戏剧学研究的专家,十余年来他撰写的《中西戏剧文化交流史》《民族戏剧学》《丝绸之路戏剧文化研究》等书,在民族学、戏剧学学界享有盛誉。新近由陕西师范大学出版总社出版发行的《民族戏剧文化大视野》是他在上述著作基础上形成的更为优秀经典的学术专著,为当今方兴未艾的民族戏剧学研究提供了强有力学科理论支撑。     

产业共性技术扩散中政府作用最优力度分析——基于变换的Bass模型

基于一定理论假设将Bass模型中技术扩散的内部影响因素和外部影响因素分别与市场作用和政府作用对应起来,并着眼于政府作用对市场作用的“挤出”效应建立起政府作用与市场作用之间的函数关系,以此来对Bass模型进行变换,使其能刻画政府作用对产业共性技术扩散速度和时间路径的影响。基于变换的Bass模型,以最大化技术扩散速度为目标构建最优化问题以求得政府作用最优力度,由最优化问题可知政府作用对市场作用的“挤出”效应越大,最优政府作用力度就应该越小。还基于相关数据进行了数值模拟分析,并且验证了模型的有效性。研究认为:由于存在政府干预对市场作用的“挤出”效应,在促进产业共性技术扩散中需要把握最优的干预力度即政府作用最优力度,在量化政府作用和市场作用的基础上,求解出来的政府作用最优力度系数可为政府有效和适当干预技术扩散提供理论上的一个尺量。     

王国维“通人之学”与“专人之学”的尺短寸长

王国维“通人之学”“专人之学”等学术思想是中国学术研究转型的重大创新,通过对王国维学术成长的梳理、学术成果的分析、学术思想的论证,对“静安之学”进行了全面系统的研究。研究认为,王国维凭借厚实的知识贮备,批判地继承西方哲学理论与中国古代哲学思想,在构建中国大文科的学科体系、研究文史哲的学术体系和中国学者的学术话语体系方面做出了全面系统实践,取得重大进展和开创性成果,堪称开一代风气的大学者;王国维以创辟胜解、通方知类的学术思辨,创立二重证据方法,探索出一条由“通人之学”到“专人之学”学问研究蹊径。系统审读、反思静安之学,对我们严肃读书风气、匡正学问研究态度、提倡学术争鸣、甄别解决知识产权争端、清除学术造假现象、规范学术研究流程,能够起到见贤思齐、弃旧图新之作用。     

Tests for the two-sample problem based on empirical probability measures

Tests are proposed for the equality of two unknown distributions. For empirical probability measures that are defined for samples from the two distributions, the proposed tests are based on the supremum of the absolute differences between the corresponding empirical probabilities, the supremum being taken over all possible events (Borel sets). In contrast, competing EDF tests compare only empirical probabilities of a subclass of Borel sets. The proposed tests are compared for simulated samples to the Kolmogorov-Smirnov, Cramér-von Mises, Kuiper, and Mann-Whitney-Wilcoxon tests     

Sample size determinations when two binomial proportions are very small

Sample size determination for testing the hypothesis of equality of proportions with a specified type I and type I1 error probabilitiesis of ten based on normal approximation to the binomial distribution. When the proportionsinvolved are very small, the exact distribution of the test statistic may not follow the assumed distribution. Consequently, the sample size determined by the test statistic may not result in the sespecifiederror probabilities. In this paper the author proposes a square root formula and compares it with several existing sample size approximation methods. It is found that with small proportion (p≦.01) the squar eroot formula provides the closest approximation to the exact sample sizes which attain a specified type I and type II error probabilities. Thes quare root formula is simple inform and has the advantage that equal differencesare equally detectable.     

On f-tests and linear hypothesis in a general linear model

A simple method of setting linear hypotheses testable by F-tests in a general linear model when the covariance matrix has a general form and is completely unknown, is provided. With some additional conditions imposed on the covariance matrix, there exist the UMP invariant tests of certain linear hypotheses. We derive them to compare the powers with those of F-tests obtained under no restrictions on the covariance matrix. The results are illustrated in a multiple regression model with some examples.     

Option pricing for generalized distributions

The Black Scholes formula has been widely used to price financial instruments. The derivation of this formula is based on the assumption of lognormally distributed returns which is often in poor agreement with actual data. An option pricing formula based on the generalized beta of the second kind (GB2) is presented. This formula includes the Black Scholes formula as a special case and accommodates a wide variety of nonlognormally distributed returns. The sensitivity of option values to departures from the skewness and kurtosis associated with the lognormal distribution is investigated.     

Some Observations,a Suggestion,and Some Comments on the Conway-Roberts Article

This article provides new tools for the evaluation of dynamic stochastic general equilibrium (DSGE) models and applies them to a large-scale new Keynesian model. We approximate the DSGE model by a vector autoregression, and then systematically relax the implied cross-equation restrictions and document how the model fit changes. We also compare the DSGE model's impulse responses to structural shocks with those obtained after relaxing its restrictions. We find that the degree of misspecification in this large-scale DSGE model is no longer so large as to prevent its use in day-to-day policy analysis, yet is not small enough to be ignored.     

Distribution of the sum of independent generalized logarithmic series variables

Jain and Gupta (1973) have given a generalized logarithmic series distribution which, for β = 1, reduces to the logarithmic series distribution. In this note we obtain the distribution of the sum of independent generalized logarithmic series variables. This distribution conforms, in a special case, to the First-type Stirling distribution (Patil and Wani, 1965) and would be useful in estimation theory.