Comparing relative importance of the same component in a series system in two environments

The relative performance of a component of a series system in two different environments is considered. The conditional probability of the failure of the system due to the failure of the specified component given that the system failed before time t is regarded as a measure of relative importance of the component to the system. A U-statistic test for checking the equality of the relative importance of the component to the system in two different environments against the alternative that the relative importance is smaller in one of the environments, is proposed. Some simulation results for estimating the power of the test are reported. The proposed test is applied to one real data set and it is seen that a different aspect of the data is brought out by this comparison than that by the comparisons of the absolute importance functions such as the subsurvival functions, considered in earlier studies.     

Models and methods for pairing data

This paper deals with models and methods for count data derived from observations on pairing phenomena. Pairs formed from “similar” members are excluded. Various models are considered and analyzed. Particular emphasis is on developing methods for testing whether particular pairs are prone to occur more or less often than expected by chance.     

Approximate optimal allocation in repeated sampling from a finite population

Samples of size n are drawn from a finite population on each of two occasions. On the first occasion a variate x is measured, and on the second a variate y. In estimating the population mean of y, the variance of the best linear unbiased combination of means for matched and unmatched samples is itself minimized, with respect to the sampling design on the second occasion, by a certain degree of matching. This optimal allocation depends on the population correlation coefficient, which previous authors have assumed known. We estimate the correlation from an initial matched sample, then an approximately optimal allocation is completed and an estimator formed which, under a bivariate normal superpopulation model, has model expected mean square error equal, apart from an error of order n^-2, to the minimum enjoyed by any linear, unbiased estimator.     

On a multiple endpoints testing problem

In a clinical trial comparing drug with placebo, where there are multiple primary endpoints, we consider testing problems where an efficacious drug effect can be claimed only if statistical significance is demonstrated at the nominal level for all endpoints. Under the assumption that the data are multivariate normal, the multiple endpoint-testing problem is formulated. The usual testing procedure involves testing each endpoint separately at the same significance level using two-sample t-tests, and claiming drug efficacy only if each t-statistic is significant. In this paper we investigate properties of this procedure. We show that it is identical to both an intersection union test and the likelihood ratio test. A simple expression for the p-value is given. The level and power function are studied; it is shown that the test may be conservative and that it is biased. Computable bounds for the power function are established.     

从1929看2009,经济危机下的中国电影

1929年的美国和2009年的中国都同样处在经济危机的寒潮之下,对比二者电影业的发展状况,分析经济危机对电影业产生的诸多影响,可以看出：首先,由于＂口红效应＂的影响,中美电影在经济危机中都出现了票房的大幅攀升,特别是中国电影增长迅速;其次,危机中的电影技术都得到了进一步的发展,如同1929年声音技术的运用一样,2009年的中国电影则是3D技术崭露头角,3D电影以及3D银幕的数量激增;再次,危机中电影内容普遍具有疗伤倾向,无论是当年美国盛行的歌舞片或是2009年中国主旋律电影的商业化,无一例外;最后,从娱乐产业的更迭趋势来看,1929年美国的百老汇逐渐衰落,电影逐渐取而代之。2009年的中国则是互联网迅速发展的一年,媒介融合趋势下电影的传播介质可能也会发生相应变化。     

An exploratory analysis of composite choices: Weighing rationality versus irrationality

Humans are engineered neurologically to make rational and irrational choices. This paper introduces a new paradigm for decision making – a composite choice model – in which economic agents are constantly weighing rationality versus irrationality when encountering options. In an exploratory, deterministic, two-period model, an assumption of a two-way cross-embedment (i.e., a two-way interaction between the rational and irrational components) results in a paradoxical phenomenon, an outcome of either tending toward bliss or abyss at the end of the first period. This implies, for instance, a psychological struggle between two selves within the mind. The paradigm proposed is compared to the dual-process theories recently developed by the cognitive sciences. Future research will explore implications for public policy design and implementation.     

The Dutch people and the euro: A structural equations analysis relating national identity and economic expectations to attitude towards the euro

National identity, macro and micro economic expectations affect the attitude toward the euro. In a study in The Netherlands, data were collected and relationships between the latent concepts were modelled with LISREL. In the best fitting model, national identity has a direct and an indirect effect on attitude, respectively, an unstructured and a structured effect. The indirect effect is mediated by macro and micro expectations. Macro expectations also have a direct and an indirect effect. The indirect effect is mediated by micro expectations. On one hand, macro expectations form a strong link between national identity and attitude. On the other hand, macro expectations have a strong direct effect on attitudes. The euro is mainly perceived and evaluated in a macro-economic perspective.PsycINFO classification: 2229; 3920     

A study of BIB designs through support matrices

This paper deals with the existence and nonexistence of BIB designs with repeated blocks. The approach is an algebraic one. The concept of a support matrix is introduced and some of its basic properties are noted. Some basic examples of support matrices are given when the block size is 3. The connection between full column rank proper support matrices and irreducible designs is explored and some examples of such matrices are given.     

Some new factor screening designs using the search linear model

Factor screening designs for searching two and three effective factors using the search linear model are discussed. The construction of such factor screening designs involved finding a fraction with small number of treatments of a 2^m factorial experiment having the property P_2t (no 2t columns are linearly dependent) for t=2 and 3. A ‘Packing Problem’ is introduced in this connection. A complete solution of the problem in one case and partial solutions for the other cases are presented. Many practically useful new designs are listed.     

Goodness-of-fit tests for a heavy tailed distribution

We study the Kolmogorov–Smirnov test, Berk–Jones test, score test and their integrated versions in the context of testing the goodness-of-fit of a heavy tailed distribution function. A comparison of these tests is conducted via Bahadur efficiency and simulations.