Inferences on the lognormal mean for complete samples

In many engineering problems it is necessary to draw statistical inferences on the mean of a lognormal distribution based on a complete sample of observations. Statistical demonstration of mean time to repair (MTTR) is one example. Although optimum confidence intervals and hypothesis tests for the lognormal mean have been developed, they are difficult to use, requiring extensive tables and/or a computer. In this paper, simplified conservative methods for calculating confidence intervals or hypothesis tests for the lognormal mean are presented. In this paper, “conservative” refers to confidence intervals (hypothesis tests) whose infimum coverage probability (supremum probability of rejecting the null hypothesis taken over parameter values under the null hypothesis) equals the nominal level. The term “conservative” has obvious implications to confidence intervals (they are “wider” in some sense than their optimum or exact counterparts). Applying the term “conservative” to hypothesis tests should not be confusing if it is remembered that this implies that their equivalent confidence intervals are conservative. No implication of optimality is intended for these conservative procedures. It is emphasized that these are direct statistical inference methods for the lognormal mean, as opposed to the already well-known methods for the parameters of the underlying normal distribution. The method currently employed in MIL-STD-471A for statistical demonstration of MTTR is analyzed and compared to the new method in terms of asymptotic relative efficiency. The new methods are also compared to the optimum methods derived by Land (1971, 1973).     

An Easily Implemented Generalised Inverse Gaussian Generator

Using the ‘ratio’ method an easily implemented algorithm is derived for the generalised inverse Gaussian distribution. Computer timings and efficiency calculations show that the procedure is fast over a wide range of distribution parameter values.     

Statistical techniques in stereology

Stereology typically concerns estimation of properties of a geometric structure from plane section information. This paperprovides a brief review of some statistical aspects of this rapidly developing field, with some reference to applications in the earth sciences. After an introductory discussion of the scope of stereology, section 2 briefly mentions results applicable when no assumptions can be made about the stochastic nature of the sampled matrix, statistical considerations then arising solelyfrom the ‘randomness’ of the plane section. The next two sections postulate embedded particles of specific shapes, the particular case of spheres being discussed in some detail.

References are made to results for ‘thin slices’ and other prob-ing mechanisms. Randomly located convex particles, of otherwise arbitrary shape, are discussed in section 5 and the review concludes with a specific application of stereological ideas to some data on neolithic mining.     

New High-Speed Computing Devices

“One method of error analysis (not the one we will use) is based upon the principles of mathematical statistics. Unfortunately, statistical methods can only be meaningfully applied when one has large amounts of data for a given system. In many cases … these large quantities of data are not available … then statistical methods are not applicable, and some other methods must be devised.”     

依托渝怀铁路实施以路兴区发展战略

结合渝怀线的现有资源和经济状况，采用定性和定量相结合的方法分析了渝怀经济带在西部大开发中的地位、作用及近远期发展战略和思路。     

Criticism of the predictive distribution

The predictive distribution is a mixture of the original distribution model and is used for predicting a future observation. Therein, the mixing distribution is the posterior distribution of the distribution parameters in the Bayesian inference. The mixture can also be computed for the frequentist inference because the Bayesian posterior distribution has the same meaning as a frequentist confidence interval. I present arguments against the concept of predictive distribution. Examples illustrate these. The most important argument is that the predictive distribution can depend on the parameterization. An improvement of the theory of the predictive distribution is recommended.     

周穆王凿空西域三千年祭

本文以《穆天子传》为主要研究对象,并以详实的资料论证了西周穆王在三千年前远征西域的史实,肯定了周穆王为开通西域的第一人及其历史功绩,从而否定了张骞凿空西域的传统说法。文中对《穆天子传》一书的出土与整理经过,成书年代与作者,内容与性质,以及文献价值等,都有详尽的论述。     

西部股票市场绩效研究与发展建议

研究西部股票市场对西部经济发展的作用与影响，认为提高西部股票市场的运作效率，有助于促进西部投资的增长。研究结果表明，要解决西部资金短缺状况，必须加快西部经济货币化进程，大力培育西部股票市场。     

Little naked pangs of the self: the real performance of the self and the function of trust in Goffman's action theory

The aim of this article is to discuss some of the leading features of Erving Goffman's action theory as an alternative to the ‘orthodox’ paradigms of sociology, viewed as a structuralist and functionalist science that defines social constructs by their shared rules and values, and as a drifting of action, in the sense of intention, toward an individualistic version. The author examines Goffman's shift of the focus of attention from the boundaries of a social sense of action to the social dialectic of ‘defining a situation’ (W. Thomas) as conducted by the social actors in a renewal of Simmel's ‘empowering covenants’ (wechselwirkung) in the multiple casual social connections that make up the ‘social buzz’ in a society. The author moreover discusses Goffman's action as a kind of playacting regulating cognitive and expressive face-to-face ‘traffic’ between the social actors. This relational dynamic creates an interactive play based on encounters – in which one's opening to another is fraught with risks of deception – regulated by trust as a central resource for social interactions. Trust, in its interpersonal and systemic variants, constitutes a universal social datum and an elementary precondition for social exchanges and the cooperation between individuals. Trust, thus, functions as comparer between reciprocal expectations and a regulator of freedom tending to the stability of the social system.     

Adaptive interval estimation in one-way random effects models

Two-stage procedures are introduced to control the width and coverage (validity) of confidence intervals for the estimation of the mean, the between groups variance component and certain ratios of the variance components in one-way random effects models. The procedures use the pilot sample data to estimate an “optimal” group size and then proceed to determine the number of groups by a stopping rule. Such sampling plans give rise to unbalanced data, which are consequently analyzed by the harmonic mean method. Several asymptotic results concerning the proposed procedures are given along with simulation results to assess their performance in moderate sample size situations. The proposed procedures were found to effectively control the width and probability of coverage of the resulting confidence intervals in all cases and were also found to be robust in the presence of missing observations. From a practical point of view, the procedures are illustrated using a real data set and it is shown that the resulting unbalanced designs tend to require smaller sample sizes than is needed in a corresponding balanced design where the group size is arbitrarily pre-specified.