Extending the empirical likelihood by domain expansion

We extend the empirical likelihood beyond its domain by expanding its contours nested inside the domain with a similarity transformation. The extended empirical likelihood achieves two objectives at the same time: escaping the “convex hull constraint” on the empirical likelihood and improving the coverage accuracy of the empirical likelihood ratio confidence region to $O(n^{-2})$ . The latter is accomplished through a special transformation which matches the extended empirical likelihood with the Bartlett corrected empirical likelihood. The extended empirical likelihood ratio confidence region retains the shape of the original empirical likelihood ratio confidence region. It also accommodates adjustments for dimension and small sample size, giving it good coverage accuracy in large and small sample situations. The Canadian Journal of Statistics 41: 257–274; 2013 © 2013 Statistical Society of Canada     

The Harris Extended Exponential Distribution

A new lifetime distribution is proposed and studied. The Harris extended exponential is obtained from a mixture of the exponential and Harris distributions, which arises from a branching process. Several structural properties of the new distribution are discussed, including moments, generating function and order statistics. The new distribution can model data with increasing or decreasing failure rate. The shape of the hazard rate function is controlled by one of the added parameters in an uncomplicated manner. An application to a real dataset illustrates the usefulness of the new distribution.     

Estimating pareto quantiles using two order statistics

Asymptotically best linear unbiased estimators of the population quantiles for the location-scale Pareto distribution with fixed shape parameter are obtained using two suitably chosen order statistics. Formulae for the appropriate order statistics, coefficients, variances, and asymptotic relative efficiencies (relative to the usual non-parametric estimator for quantiles) are given     

The Impact of the Online Channel on Retailers' Performances: An Empirical Evaluation

The use of the Internet as an additional sales channel offers traditional retailers opportunities to reach expanded markets while improving the efficiency of their operations. Although the potential benefits of the online channel are clear, there are significant variations in the scope and depth of online channel use among retailers. Drawing from data on more than 100 publicly traded companies, this study examines the impact of online‐channel use on retailers’ performance. The results suggest that the online channel provides significant improvements in sales, cost, inventory, and return on investments. In addition, we find that the timing of online‐channel adoption does not play a significant role in performance improvement, but having a local store presence does.     

An international trade model to capture linkages among supply-constrained economies

The development of a country's domestic and international markets depends on its own actions as much as on those of its trading partners. The study of market linkages is thus vital for policy making. Borrowing from the conceptual framework of Leontief's input-output analysis and from the national accounts equation, this paper presents a new model to calculate multilateral trade multipliers while minimizing data requirements. The novelty of the approach consists in the column-wise (supply-oriented) normalization of trade as opposed to the row-wise (demand-oriented) normalization that prevails in the literature. The explanatory power of the model has been successfully tested on data that refer to 1973–1974. Divergence from reality inevitably reflects the great fluidity that characterized trade during that period. Although most successful when applied to trade among supply-oriented economies (such as those of socialist or developing countries), at present empirical tests have been run only for a handful of OECD and OPEC countries.     

Asymptotic expansions for the distributions of statistics based on a correlation matrix

An asymptotic expansion is given for the distribution of the α-th largest latent root of a correlation matrix, when the observations are from a multivariate normal distribution. An asymptotic expansion for the distribution of a test statistic based on a correlation matrix, which is useful in dimensionality reduction in principal component analysis, is also given. These expansions hold when the corresponding latent root of the population correlation matrix is simple. The approach here is based on a perturbation method.     

四川主要地区鸡大肠杆菌病病原分离鉴定及免疫预防研究(二)——免疫期的测定

为探明接种E.coli氢氧化铝多价灭活苗鸡只血清中E.coli抗体消长规律,以及血清抗体与保护率的关系,以便合理制定免疫程序,我们采用试管凝集法对免疫鸡只进行血清中E.coli抗体测定,并对不同免疫期和不同抗体水平的鸡进行同源菌株的攻毒保护试验。结果表明:抗体凝集价与攻毒保护率的关系是:1:32=90％;≥1:64=100％;1:24=50％。抗体消长规律是:免疫一周后抗体凝集价达1:32,第三周达1:128,第4—6周达最高峰1:190,以后逐渐下降,第15周降至1:24。免疫期为15周,免疫临界线初步拟定在1:24。建议当鸡(特别是种鸡和蛋鸡)血清抗体水平处于免疫临界线时,应适时接种,以有效地预防本病。     

试论公证在电子合同中的应用价值

随着网络经济时代的到来, 人们通过缔结电子合同来进行交易的情况越来越多。由于电子合同存在种种难以预测的特殊风险, 故而需要对其加以法律控制, 而公证作为国家法律证明手段, 若应用到电子合同中, 势必能降低电子合同的特殊风险。