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51.
Five sampling schemes (SS) for price index construction – one cut-off sampling technique and four probability-proportional-to-size (pps) methods – are evaluated by comparing their performance on a homescan market research data set across 21 months for each of the 13 classification of individual consumption by purpose (COICOP) food groups. Classifications are derived for each of the food groups and the population index value is used as a reference to derive performance error measures, such as root mean squared error, bias and standard deviation for each food type. Repeated samples are taken for each of the pps schemes and the resulting performance error measures analysed using regression of three of the pps schemes to assess the overall effect of SS and COICOP group whilst controlling for sample size, month and population index value. Cut-off sampling appears to perform less well than pps methods and multistage pps seems to have no advantage over its single-stage counterpart. The jackknife resampling technique is also explored as a means of estimating the standard error of the index and compared with the actual results from repeated sampling. 相似文献
52.
Since multi-attribute control charts have received little attention compared with multivariate variable control charts, this research is concerned with developing a new methodology to employ the multivariate exponentially weighted moving average (MEWMA) charts for m-attribute binomial processes; the attributes being the number of nonconforming items. Moreover, since the variable sample size and sampling interval (VSSI) MEWMA charts detect small process mean shifts faster than the traditional MEWMA, an economic design of the VSSI MEWMA chart is proposed to obtain the optimum design parameters of the chart. The sample size, the sampling interval, and the warning/action limit coefficients are obtained using a genetic algorithm such that the expected total cost per hour is minimized. At the end, a sensitivity analysis has been carried out to investigate the effects of the cost and the model parameters on the solution of the economic design of the VSSI MEWMA chart. 相似文献
53.
Software packages usually report the results of statistical tests using p-values. Users often interpret these values by comparing them with standard thresholds, for example, 0.1, 1, and 5%, which is sometimes reinforced by a star rating (***, **, and *, respectively). We consider an arbitrary statistical test whose p-value p is not available explicitly, but can be approximated by Monte Carlo samples, for example, by bootstrap or permutation tests. The standard implementation of such tests usually draws a fixed number of samples to approximate p. However, the probability that the exact and the approximated p-value lie on different sides of a threshold (the resampling risk) can be high, particularly for p-values close to a threshold. We present a method to overcome this. We consider a finite set of user-specified intervals that cover [0, 1] and that can be overlapping. We call these p-value buckets. We present algorithms that, with arbitrarily high probability, return a p-value bucket containing p. We prove that for both a bounded resampling risk and a finite runtime, overlapping buckets need to be employed, and that our methods both bound the resampling risk and guarantee a finite runtime for such overlapping buckets. To interpret decisions with overlapping buckets, we propose an extension of the star rating system. We demonstrate that our methods are suitable for use in standard software, including for low p-value thresholds occurring in multiple testing settings, and that they can be computationally more efficient than standard implementations. 相似文献
54.
AbstractThe present study confirms the influential role of a positively and a negatively correlated auxiliary variables in enhancing the precision of estimates of current population mean in two occasion rotation (successive) sampling. Exponential-type estimators of current population mean have been proposed for three different situations: (i) the information on a positively correlated auxiliary variable is readily available on both occasions (ii) the information on a negatively correlated auxiliary variable is readily available on both occasions and (iii) the information on both positively and negatively correlated auxiliary variables are readily available on both the occasions. The characteristics of the proposed estimators have been explored and their efficacious performances are compared with the natural and recent contemporary estimators. Optimum replacement strategies of the proposed estimation procedures have been formulated. Simulation and empirical studies are carried out to justify the proposition of the proposed estimators and appropriate recommendations have been put forward to the survey practitioners. 相似文献
55.
为检验中国中央银行是否已将金融市场状况纳入货币政策的框架,采用HTVPVAR模型的脉冲响应构建中国金融市场状况指数,检验结果显示:以金融市场状况指数为转换变量的STR模型形式的利率规则能较好地拟合实际数据,政策利率对通货膨胀缺口的变动存在非线性调整,且金融市场的景气(不景气)将增强(减弱)货币政策对通货膨胀缺口的反应程度。 相似文献
56.
针对传统基于继电器控制的稳压电源在带负载工作时,档位切换常常伴随火弧现象的问题,设计了一种可广泛
应用于此类稳压电源上的自适应去火弧技术:使用光耦和多级运放完成对零点和电压电流的采样;基于单片机的10量,
实现对继电器的驱动和控制;基于RCC自激震荡原理为系统提供稳定电源;设计了稳压器的完整软件系统程序,并在软
件中应用自适应去火弧算法。实验结果表明:自适应去火弧技术,能够有效地规避火弧现象的产生,并能够根据条件作
出调整。采用自适应去火弧技术的稳压系统达到了设计目标,延长了系统工作寿命。 相似文献
57.
Omer Ozturk 《统计学通讯:模拟与计算》2016,45(10):3568-3583
In this article, we develop an estimator for a population variance based on a multi-ranker ranked set sampling design. In a multi-ranker design, the units are ranked by more than one ranker allowing ties whenever the confidence level of the rankers is low. The ranking information of all rankers is then combined in a meaningful way to create a single measure. This measure is used to construct the sampling design and a new estimator for the population variance. The article investigates the bias and relative efficiency of the proposed variance estimator. It is shown that the new estimator performs as good as or better than its competitors in the literature. 相似文献
58.
59.
Marcel de Toledo Vieira Maria de Fátima Salgueiro Peter W. F. Smith 《Journal of applied statistics》2016,43(7):1310-1321
We investigate the impacts of complex sampling on point and standard error estimates in latent growth curve modelling of survey data. Methodological issues are illustrated with empirical evidence from the analysis of longitudinal data on life satisfaction trajectories using data from the British Household Panel Survey, a national representative survey in Great Britain. A multi-process second-order latent growth curve model with conditional linear growth is used to study variation in the two perceived life satisfaction latent factors considered. The benefits of accounting for the complex survey design are considered, including obtaining unbiased both point and standard error estimates, and therefore correctly specified confidence intervals and statistical tests. We conclude that, even for the rather elaborated longitudinal data models that were considered, estimation procedures are affected by variance-inflating impacts of complex sampling. 相似文献
60.
刘殿祥 《汕头大学学报(人文社会科学版)》2007,23(4):66-71
闻一多作为中国现代诗人和现代学者,在现代文化史上留下了丰富的文本文献,其著作的出版经过了一个漫长的过程,其版本的演变比较复杂,全集的出版经历了从旧版到新版的演变。《闻一多全集》的编印具有多方面的价值,不仅有过鲜明的政治意义,尤其具有丰富的文化意义,即在中国现代文学史和现代学术史以及中国现代知识分子的精神变迁史方面的"标本"意义。 相似文献