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81.
V.K. Srivastava 《Journal of statistical planning and inference》1982,6(3):297-299
This paper presents a class of estimators for the mean of a normal population and determines the conditions on characterizing scalars under which the class of estimators uniformly dominates over the conventional sample mean according to the mean-square-error criterion. 相似文献
82.
东亚区域经济合作的约束条件及主导力量——“10+1”合作模式可行性研究 总被引:3,自引:0,他引:3
在全球各区域经济合作中,东亚区域经济合作处于制度推进的初级阶段。在东亚合作约束条件序列中,经济整合度和贸易开放约束较小,主导国和主导力量约束次之,政治和文化约束最大。与欧洲和北美区域经济合作不同,东亚文化背景殊异;百年殖民历史伤痛犹新;放弃国家主权疑虑重重,还没有形成能够协调各方利益和促进区域经济合作的稳定制度机制。在内部和外部条件限制下,东亚经济一体化只能通过三个相互割裂的“东盟10 l”机制“迂回”推进,而且在相当长时期合作采取的是自由贸易区方式。 相似文献
83.
3G“杀手级”业务的产生和培育 总被引:1,自引:1,他引:0
3G时代的到来无疑为电信市场的发展带来了机遇和挑战,到底怎样的电信业务能在新时代中脱颖而出,成为业内人士心驰神往的“杀手级”业务,的确是个耐人寻味的问题。在对“杀手级”业务所应具备的基本条件作探讨的同时,对“杀手级”业务的培育策略进行了分析,认为“杀手级”业务本不存在,它的形成是市场多方因素共同努力的结果。 相似文献
84.
A dynamic model of a heterogeneous population is studied. Particles belonging to a population are divided, at every time t, into a finite number of classes according to their types and the partition changes over time. The role of the occupancy numbers, namely the cardinality of each class, is highlighted. The relationship between the stochastic process of occupancy numbers and the process of particle types is analyzed. The main goal of this paper is the estimation of the lifetime of each particle at a given time t, when the observed data are the history of the process of the number of dead particles up to t. Furthermore, a discrete time approximation of the filter is given. 相似文献
85.
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. 相似文献
86.
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. 相似文献
87.
引入域上典型群的生成问题所得的成果;对局部环R上典型群生成问题研究,构造度量函数及一平延,为局部环R上典型群向域F上的典型群导入,给出典型群的非双曲型. 相似文献
88.
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. 相似文献
89.
Fluctuations in aggregate crime rates contrary to recent shifts in the age distribution of the U.S. population have cast doubt on the predictive power of the age–crime hypothesis. By examining a longer time horizon, back to the early 1930s, we show that the percentage of the young population is a robust predictor of the observed large swings in the U.S. murder rate over time. However, changes in the misery index—the sum of the inflation and unemployment rates—significantly contribute to explaining changes in the murder rate. This applies, in particular, to those changes that are at odds with the long-run trend of the U.S. age distribution, such as the decline in the murder rate in the latter part of the 1970s or its increase starting around the middle of the 1980s. 相似文献
90.