A simple and accurate inference procedure for the difference of failure intensities from two exponential distributions

A third order asymptotic method is proposed to obtain approximate observed levels of significance and confidence intervals for the difference of failure intensities from two independent exponential distributions. The proposed method is extremely accurate even for very small sample sizes and it is simple to use. Numerical examples are used to illustrate the difference in accuracy between the proposed method and methods discussed in Bain, Shiue & Engelhardt (1993) and Yu & Burdick (1994), Extensions to censored samples and cost considerations are also discussed.     

On approximating the central and noncentral multivariate gamma distributions

In this paper a finite series approximation involving Laguerre polynomials is derived for central and noncentral multivariate gamma distributions. It is shown that if one approximates the density of any k nonnegative continuous random variables by a finite series of Laguerre polynomials up to the (n₁, …, n_k)th degree, then all the mixed moments up to the order (n₁, …, n_k) of the approximated distribution equal to the mixed moments up to the same order of the random variables. Some numerical results are given for the bivariate central and noncentral multivariate gamma distributions to indicate the usefulness of the approximations.     

Innovation by Teams in Shanghai,China: Cooperative Goals for Group Confidence and Persistence*

Organizations increasingly ask teams to stimulate innovation but research is needed to identify the conditions when teams have the confidence and persistence to innovate successfully. Using the concepts of cooperation, competition, group potency and initiative, this study proposes that relationships where team members believe that their goals are cooperative in that one person's goal attainment helps others reach their goals lay the foundation for innovation. Specifically, cooperative goals convince team members that they have the group potency to complete a range of tasks and the initiative to persist to overcome obstacles and innovate. In contrast, competitive, negatively related goals and independent, unrelated goals are hypothesized to undermine confidence, persistence and innovation. Group members from 101 teams from various organizations in Shanghai, China, completed a survey with measures of cooperative, competitive and independent goals, group potency, and initiative; their project leader completed the measure of innovation. Structural equation analysis supports the theoretical framework that cooperative goals help group members develop the confidence of group potency and the initiative to persist to accomplish tasks and innovate. These results suggest that cooperative goals and group potency and initiative are important conditions that help teams innovate for organizations and thereby specify conditions that can help groups realize their potential to achieve innovation for organizations.     

刘向《诗》学家法研究

刘向之《诗经》学家法,前人每有论及。然其论据及研究方法,均仍有可改善之处。本文从家学、异文比较、《诗》说比较三方面,考论刘向之《诗》学家法,以图全面分析刘向《诗》学家法的问题,并希望由此而于两汉《诗》学研究有所裨益。