共查询到20条相似文献,搜索用时 531 毫秒
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SPSS(StatisticalPackageforthesocialscience)社会科学统计软件包是世界上著名的统计分析软件之一。它和SAS(Sta-tisticalAnalysisSystem,统计分析系统)及BMDP(Biomedicalp... 相似文献
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SPSS统计分析研究的有利工具 总被引:1,自引:0,他引:1
PSS(statisticalpackageforthesocialscience)———社会科学软件包是世界上著名的统计分析软件之一。它和SAS(StatisticalAnalysisSystem,统计分析系统)、BMDA(BiomedicalPrograms,生物医学程序)并称为国际上最有影响的三大统计软件。SPSS目前已应用于经济学、生物学、医学以及工、农、林业、商业和金融等各个领域,在社会科学和自然科学各个领域发挥了巨大作用。SPSS有两个窗口,一个是SPSS数据编辑窗口,另一个是SPSS输… 相似文献
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一、引言在世界上任何一个国家 ,几乎所有的汽车保险人都采用了无赔款优待系统 ,即所谓的BMS(Bonus MalusSystem)。在该系统中 ,保险公司将根据投保人以往年份的索赔情况调整其续期保费。通常的原则是 ,上一保险年度发生的索赔次数越多 ,次年的续期保费将越高。反之 ,如果上一保险年度没有发生索赔 ,保险公司将降低投保人的续期保费。毫无疑问 ,保险公司调整投保人续期保费的主要目的之一就是为了公平投保人的保费负担 ,使高风险的投保人缴纳相对较高的保险费。但是 ,实证研究结果表明 (参见文献 [1]) ,保险公司目前应用… 相似文献
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Linux是一个优秀的网络操作系统,它可与多种网络集成。在统计系统内很多省的WEB服务器采用Lin-ux-Apahce。由于客户机大量采用Windows9X,让Win-dows客户机共享Linux系统中的资源成为一个重要的问题。这种Linux、Windows网络集成是通过Samba来实现的,Widnows用户可以方便地通过网上邻居访问Lin-ux系统上的资源。 Samba是一组软件包,使Linux支持SMB协议,该协议由TCP/IP实现,它是wingdows网络文件和打印共享的基础,负责处理和使… 相似文献
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数据库应用新技术—知识发现(KDD) 总被引:2,自引:0,他引:2
引言随着信息时代的到来 ,社会、政治、经济等等方面的信息量急剧增长 ,这些信息是一种宝贵的信息资源 ,其背后隐藏着许多重要的信息 ,可以很好地支持人们的决策。目前的数据库系统 (DBMS)提供的查询手段一般只限于一些基本的数据库操作和聚集函数 ,例如OLAP所提供的决策用数据就是这样产生的。因此通过DBMS只能对数据“粗加工” ,并从中获得一些初级的综合信息。数据库中常常蕴涵着规则 (rules)、规律 (regurlarities)、论断 (inference)之类的高层次信息或知识 ,这些信息在决策生成的过程中具有重… 相似文献
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William Navidi 《统计学通讯:理论与方法》2013,42(2):213-220
Poisson regression and case-crossover are frequently used methods to estimate transient risks of environmental exposures such as particulate air pollution on acute events such as mortality. Roughly speaking, a case-crossover design results from a Poisson regression by conditioning on the total number of failures. We show that the case-crossover design is somewhat more generally applicable than Poisson regression. Stratification in the case-crossover design is analogous to Poisson regression with dummy variables, or to a marked Poisson regression. Poisson regression makes it possible to express case-crossover likelihood functions as multinomial likelihoods without making reference to cases, controls, or matching. This derivation avoids the counterintuitive notion of basing inferences on exposures that occur post-failure. 相似文献
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The Poisson regression is very popular in applied researches when analyzing the count data. However, multicollinearity problem arises for the Poisson regression model when the independent variables are highly intercorrelated. Shrinkage estimator is a commonly applied solution to the general problem caused by multicollinearity. Recently, the ridge regression (RR) estimators and some methods for estimating the ridge parameter k in the Poisson regression have been proposed. It has been found that some estimators are better than the commonly used maximum-likelihood (ML) estimator and some other RR estimators. In this study, the modified Jackknifed Poisson ridge regression (MJPR) estimator is proposed to remedy the multicollinearity. A simulation study and a real data example are provided to evaluate the performance of estimators. Both mean-squared error and the percentage relative error are considered as the performance criteria. The simulation study and the real data example results show that the proposed MJPR method outperforms the Poisson ridge regression, Jackknifed Poisson ridge regression and the ML in all of the different situations evaluated in this paper. 相似文献
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Célestin C. Kokonendji Dominique Mizère N. Balakrishnan 《Journal of statistical planning and inference》2008
In this paper, we establish several connections of the Poisson weight function to overdispersion and underdispersion. Specifically, we establish that the logconvexity (logconcavity) of the mean weight function is a necessary and sufficient condition for overdispersion (underdispersion) when the Poisson weight function does not depend on the original Poisson parameter. We also discuss some properties of the weighted Poisson distributions (WPD). We then introduce a notion of pointwise duality between two WPDs and discuss some associated properties. Next, we present some illustrative examples and provide a discussion on various Poisson weight functions used in practice. Finally, some concluding remarks are made. 相似文献
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Posterior distributions and moment are derived for the generalized Poisson and the excess zeroes Poisson distributions.Three examples are presented where both maximum likelihood and posterior estimates are given. 相似文献
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P.C. Consul 《统计学通讯:理论与方法》2013,42(2):423-442
A new generalization of the Poisson distribution was given by Consul and Jain (1970, 73). Since then more than twenty papers, written by various researchers, have appeared on this model under the titles of Generalized Poisson Distribution (GPD), Lagrangian Poisson distribution or modified power series distribution. Here the author provides two physical models, based on differential-difference equations, which lead to the GPD. A number of axioms are given for a steady state point process which produce the generalized Poisson process. Also, the GPD is derived as the limiting distribution of the two quasi-binomial distributions based on urn models. 相似文献
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Galit Shmueli Thomas P. Minka Joseph B. Kadane Sharad Borle Peter Boatwright 《Journal of the Royal Statistical Society. Series C, Applied statistics》2005,54(1):127-142
Summary. A useful discrete distribution (the Conway–Maxwell–Poisson distribution) is revived and its statistical and probabilistic properties are introduced and explored. This distribution is a two-parameter extension of the Poisson distribution that generalizes some well-known discrete distributions (Poisson, Bernoulli and geometric). It also leads to the generalization of distributions derived from these discrete distributions (i.e. the binomial and negative binomial distributions). We describe three methods for estimating the parameters of the Conway–Maxwell–Poisson distribution. The first is a fast simple weighted least squares method, which leads to estimates that are sufficiently accurate for practical purposes. The second method, using maximum likelihood, can be used to refine the initial estimates. This method requires iterations and is more computationally intensive. The third estimation method is Bayesian. Using the conjugate prior, the posterior density of the parameters of the Conway–Maxwell–Poisson distribution is easily computed. It is a flexible distribution that can account for overdispersion or underdispersion that is commonly encountered in count data. We also explore two sets of real world data demonstrating the flexibility and elegance of the Conway–Maxwell–Poisson distribution in fitting count data which do not seem to follow the Poisson distribution. 相似文献
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Sheela Talwalker 《统计学通讯:理论与方法》2013,42(3):347-354
Multivariate normal, correlated multivariate Poisson and multiple Poisson distributions are characterized, in the class of exponential-type distributions, by the properties of the linear combinations of the variables, the properties of their cumulants and the recurance relation between the cumulants. 相似文献
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Nonparametric maximum likelihood estimation of population size based on the counting distribution 总被引:1,自引:0,他引:1
Dankmar Böhning Dieter Schön 《Journal of the Royal Statistical Society. Series C, Applied statistics》2005,54(4):721-737
Summary. The paper discusses the estimation of an unknown population size n . Suppose that an identification mechanism can identify n obs cases. The Horvitz–Thompson estimator of n adjusts this number by the inverse of 1− p 0 , where the latter is the probability of not identifying a case. When repeated counts of identifying the same case are available, we can use the counting distribution for estimating p 0 to solve the problem. Frequently, the Poisson distribution is used and, more recently, mixtures of Poisson distributions. Maximum likelihood estimation is discussed by means of the EM algorithm. For truncated Poisson mixtures, a nested EM algorithm is suggested and illustrated for several application cases. The algorithmic principles are used to show an inequality, stating that the Horvitz–Thompson estimator of n by using the mixed Poisson model is always at least as large as the estimator by using a homogeneous Poisson model. In turn, if the homogeneous Poisson model is misspecified it will, potentially strongly, underestimate the true population size. Examples from various areas illustrate this finding. 相似文献
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Adrienne W. Kemp 《统计学通讯:理论与方法》2013,42(3):571-588
The paper shows that the Heine and Euler distributions (Benkherouf and Bather, 1988) are members of a family of q-series anologues of the Poisson distribution, with similar probability mass functions, but different restrictions on their parameters, and different modes of genesis and properties. The relationships between the Heine, Euler, pseudo-Euler, Poisson and geometric distributions are explored. Illustrative data sets are discussed. 相似文献
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《Journal of statistical planning and inference》2005,128(1):79-93
We consider conditions under which parametric estimates of the intensity of a spatial–temporal point process are consistent. Although the actual point process being estimated may not be Poisson, an estimate involving maximizing a function that corresponds exactly to the log-likelihood if the process is Poisson is consistent under certain simple conditions. A second estimate based on weighted least squares is also shown to be consistent under quite similar assumptions. The conditions for consistency are simple and easily verified, and examples are provided to illustrate the extent to which consistent estimation may be achieved. An important special case is when the point processes being estimated are in fact Poisson, though other important examples are explored as well. 相似文献