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1.
The joint efforts in the USSR by the Central Planning Commission and the State Statistical Commission to develop projections of family characteristics of the Soviet population are described. The projections, based on official data for the rural and urban populations in 1987, are for the years 1991, 1996, 2001, and 2006.  相似文献   

2.
The USSR is moving from extensive to intensive type of population reproduction, not because of any governmental measures but as a reaction to objective circumstances. At present there is a reduction in the population cohort of working age. This has an adverse effect on production. And the number of the elderly is increasing; we must involve them more in the production process, in monitoring the service sphere, for instance. The infant mortality rate has declined sharply in the USSR, especially since World War II. The birthrate has also dropped, but it is still higher than in the US, France, or West Germany. Some authorities think that this (the ZPG) is a good idea, but this author thinks it is a bad idea, meaning a drop in society's productive forces. We need an active demographic policy, meaning one which ensures optimal reproduction of the population with an improvement in its health, culture, and living standard. The policy must be differentiated, as conditions vary from one part of the country to another. An example is the 1981 decree on assistance to families with children which provides for payments of 35-50 rubles/month to mothers who must stay home to look after children. The number of children per family to ensure reproduction must be 2.6 on the average. In the Central Asian republics family sizes of 4-5 children are anticipated, but in the RSFSR, Ukraine, Belorussia, and the Baltic republics the anticipated size of families is rather low. Measures must be taken to alter this by providing assistance to families with children.  相似文献   

3.
The usual maximum likelihood estimators of the parameters of the von Mises distribution are shown to perform badly in small samples. In view of this and the fact that these estimators require a large amount of computation, alternative, simpler estimators are proposed. It is shown that these estimators are at least comparable to the traditional estimators and are, in many cases, superior to them. We also apply the procedure of jackknifing to the maximum likelihood estimator of the concentration parameter of the von Mises distribution and compare the properties of the jackknifed estimator with the other estimators considered in this paper.  相似文献   

4.
Estimation of the parameter in the problem of the Nile is treated as a decision problem with squared error loss, It is shown that the minimum risk scale equivariant estimator dominates the incomplete sufficient unbiased estimators considered by Iwase and Seto, Sharper bounds for the equivariant estimator are derived which may be used to obtain the values of the same from the sample with sufficient accuracy.  相似文献   

5.
人工神经网络变量选取与隐藏单元数的确定   总被引:2,自引:0,他引:2  
根据多隐藏层所有训练样本误差平方和最小设计优化问题,求解并绘出计算流程图。Trevor等人认为隐藏单元过多比过少好,交叉验证估计(隐藏单元)正则化参数没有必要。还有一种通常做法是常常利用分类树挑选变量作为输入变量进行人工神经网络建模。而从人工神经网络与多元统计、传统回归和其他数据挖掘工具的区别和联系出发,认为这些观点和做法值得商酌;用ZIP编码实例说明隐藏单元过多不一定比过少好,实际数据分析中所需隐藏单元数的确定可以用交叉验证结合经验判断来实现,利用分类树选择的变量对于人工神经网络没有太大的效果;通过分类树删节变量以降低计算量的效果不如通过压缩隐藏单元个数降低计算量来得好;非完全问题“从简单到一般”思想与完全问题中选择所有变量的思想不矛盾。在总结了Le Cun等人的局部联结以有效降低权数思想的基础上,提出通过随机选择人工变量建立人工神经网络分布式模型系统的设想。  相似文献   

6.
Intervention-ARIMA模型在我国第三产业就业人数预测中的应用   总被引:4,自引:0,他引:4  
万平 《统计教育》2009,(9):31-33,37
本文利用Intervention—ARIMA模型对我国第三产业就业人数(1952—2006年)时间序列进行了动态拟合,重点考虑了“大跃进”对我国第三产业就业人数的干预影响,取得了很好的拟合效果,并预测了我国未来几年第三产业就业人数的发展趋势。证明了第三产业发展对缓解我国当前就业压力的积极效应。  相似文献   

7.
The population growth rate of the European dipper has been shown to decrease with winter temperature and population size. We examine here the demographic mechanism for this effect by analysing how these factors affect the survival rate. Using more than 20 years of capture-mark-recapture data (1974-1997) based on more than 4000 marked individuals, we perform analyses using open capture-mark-recapture models. This allowed us to estimate the annual apparent survival rates (probability of surviving and staying on the study site from one year to the next one) and the recapture probabilities. We partitioned the variance of the apparent survival rates into sampling variance and process variance using random effects models, and investigated which variables best accounted for temporal process variation. Adult males and females had similar apparent survival rates, with an average of 0.52 and a coefficient of variation of 40%. Chick apparent survival was lower, averaging 0.06 with a coefficient of variation of 42%. Eighty percent of the variance in apparent survival rates was explained by winter temperature and population size for adults and 48% by winter temperature for chicks. The process variance outweighed the sampling variance both for chick and adult survival rates, which explained that shrunk estimates obtained under random effects models were close to MLE estimates. A large proportion of the annual variation in the apparent survival rate of chicks appears to be explained by inter-year differences in dispersal rates.  相似文献   

8.
The population growth rate of the European dipper has been shown to decrease with winter temperature and population size. We examine here the demographic mechanism for this effect by analysing how these factors affect the survival rate. Using more than 20 years of capture-mark-recapture data (1974-1997) based on more than 4000 marked individuals, we perform analyses using open capture-mark-recapture models. This allowed us to estimate the annual apparent survival rates (probability of surviving and staying on the study site from one year to the next one) and the recapture probabilities. We partitioned the variance of the apparent survival rates into sampling variance and process variance using random effects models, and investigated which variables best accounted for temporal process variation. Adult males and females had similar apparent survival rates, with an average of 0.52 and a coefficient of variation of 40%. Chick apparent survival was lower, averaging 0.06 with a coefficient of variation of 42%. Eighty percent of the variance in apparent survival rates was explained by winter temperature and population size for adults and 48% by winter temperature for chicks. The process variance outweighed the sampling variance both for chick and adult survival rates, which explained that shrunk estimates obtained under random effects models were close to MLE estimates. A large proportion of the annual variation in the apparent survival rate of chicks appears to be explained by inter-year differences in dispersal rates.  相似文献   

9.
10.
The EM algorithm is a popular method for parameter estimation in situations where the data can be viewed as being incomplete. As each E-step visits each data point on a given iteration, the EM algorithm requires considerable computation time in its application to large data sets. Two versions, the incremental EM (IEM) algorithm and a sparse version of the EM algorithm, were proposed recently by Neal R.M. and Hinton G.E. in Jordan M.I. (Ed.), Learning in Graphical Models, Kluwer, Dordrecht, 1998, pp. 355–368 to reduce the computational cost of applying the EM algorithm. With the IEM algorithm, the available n observations are divided into B (B n) blocks and the E-step is implemented for only a block of observations at a time before the next M-step is performed. With the sparse version of the EM algorithm for the fitting of mixture models, only those posterior probabilities of component membership of the mixture that are above a specified threshold are updated; the remaining component-posterior probabilities are held fixed. In this paper, simulations are performed to assess the relative performances of the IEM algorithm with various number of blocks and the standard EM algorithm. In particular, we propose a simple rule for choosing the number of blocks with the IEM algorithm. For the IEM algorithm in the extreme case of one observation per block, we provide efficient updating formulas, which avoid the direct calculation of the inverses and determinants of the component-covariance matrices. Moreover, a sparse version of the IEM algorithm (SPIEM) is formulated by combining the sparse E-step of the EM algorithm and the partial E-step of the IEM algorithm. This SPIEM algorithm can further reduce the computation time of the IEM algorithm.  相似文献   

11.
The Cornish-Fisher expansion of the Pearson type VI distribution is known to be reasonably accurate when both degrees of freedom are relatively large (say greater than or equal to 5). However, when either or both degrees of freedom are less than 5, the accuracy of the computed percentage point begins to suffer; in some cases severely. To correct for this, the error surface in the degrees of freedom plane is modeled by least squares curve fitting for selected levels of tail probability (.025, .05, and .10) which can be used to adjust the percentage point obtained from the usual Cornish-Fisher expansion. This adjustment procedure produces a computing algorithm that computes percentage points of the Pearson type VI distribution at the above probability levels, accurate to at least + 1 in 3 digits in approximately 11 milliseconds per subroutine call on an IBM 370/145. This adjusted routine is valid for both degrees of freedom greater than or equal to 1.  相似文献   

12.
This is a history of the 1937 census of the USSR, the results of which were suppressed because of an alleged massive undercount. The author attempts to determine whether there was in fact an undercount in this census, and if so how significant it was. He concludes that those responsible were not guilty of producing a significant undercount, and in fact employed the methods required to keep the undercount to a bare mimimum.  相似文献   

13.
Selected results of a socio-demographic survey conducted in the USSR in 1985 are presented. The survey covered approximately 13 million people. Topics considered include family size, assistance to mothers of young children, birth rates, age at marriage, educational status, income, and internal migration.  相似文献   

14.
The X2 approximation to the distribution of the sample coefficient of variation of a normally distributed random variable, due to McKay 1932 is not nearly as accurate as suggested by the confirmatory studies of Fieller 1932 and Pearson 1932.The approximation will, however, be adequate in many practical situations and has the convenience of requiring nothing more than the readily available tables of x2.  相似文献   

15.
Mortality trends in the USSR from the middle of the nineteenth century to the present day are analyzed, with a focus on changes in life expectancy. The authors note that life expectancy increased up to 1964-1965, declined subsequently, and stabilized during the 1980s. Life expectancy has again started to rise since 1985. More detailed analyses of mortality differentials by sex and age and for the rural and urban populations are included. (SUMMARY IN ENG)  相似文献   

16.
A new class of estimators is introduced for the problem of estimating the mean of the selected population. These estimators are found by subtracting from the largest sample mean an estimator of its bias. The new estimators are compared with those introduced by Cohen and Sackrowitz (1982) and in terms of frequentist risk they are found to perform quite similarly.  相似文献   

17.
Surveillance to detect changes of spatial patterns is of interest in many areas such as environmental control and regional analysis. Here the interaction parameter of the Ising model, is considered. A minimal sufficient statistic and its asymptotic distribution are used. It is demonstrated that the convergence to normal, distribution is rapid. The main result is that when the lattice is large, all approximations are better in several respects. It is shown that, for large lattice sizes, earlier results on surveillance of a normally distributed random variable can be used in cases of most interest. The expected delay of alarm at a fixed level of false alarm probability is examined for some examples.  相似文献   

18.
The intra-cluster correlation is insisted on nested error regression model that, in practice, is rarely known. This article demonstrates the size in generalized least squares (GLS) F-test using Fuller–Battese transformation and modification F-test. For the balanced case, the former using strictly positive, analysis of covariance (ANCOVA) and analysis of variance (ANOVA) estimators of intra-cluster correlation can control the size for moderate intra-cluster correlations. For small intra-cluster correlation, they perform well when the numbers of cluster are large. The latter using the ANOVA estimator performs well except for small numbers of cluster. When intra-cluster correlation is large, it cannot control the size. For the unbalanced case, the GLS F-test using the Fuller–Battese transformation and the modification F-test using the strictly positive, the ANCOVA and the ANOVA estimators maintain the significance level for small total sample size and small intra-cluster correlations when there is a large variation in cluster sizes, but they perform well in controlling the size for large total sample size and small different variation in cluster sizes. Besides, Henderson’s method 3 estimator maintains the significance level for a few situations.  相似文献   

19.
Differences in population characteristics among the administrative districts of Poland are analyzed. The characteristics examined include density, place of employment, urban population growth, population employed in agriculture, and migration.  相似文献   

20.
Spatial mobility in Poland is analyzed for the period 1976-1989. The focus is on the decline in internal migration over time and its causes. The analysis includes migration between rural and urban areas as well as migration among voivodships. Factors affecting migration include changes in the age distribution; however, the authors conclude that changes in migration patterns are primarily due to socioeconomic factors, particularly the economic crises the country has faced in recent years.  相似文献   

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