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861.
A parametric marginal structural model (PMSM) approach to Causal Inference has been favored since the introduction of MSMs by Robins [1998a. Marginal structural models. In: 1997 Proceedings of the American Statistical Association. American Statistical Association, Alexandria, VA, pp. 1–10]. We propose an alternative, nonparametric MSM (NPMSM) approach that extends the definition of causal parameters of interest and causal effects. This approach is appealing in practice as it does not require correct specification of a parametric model but instead relies on a working model which can be willingly misspecified. We propose a methodology for longitudinal data to generate and estimate so-called NPMSM parameters describing so-called nonparametric causal effects and provide insight on how to interpret these parameters causally in practice. Results are illustrated with a point treatment simulation study. The proposed NPMSM approach to Causal Inference is compared to the more typical PMSM approach and we contribute to the general understanding of PMSM estimation by addressing the issue of PMSM misspecification. 相似文献
862.
A first-order random coefficient integer-valued autoregressive (RCINAR(1)) model is introduced. Ergodicity of the process is established. Moments and autocovariance functions are obtained. Conditional least squares and quasi-likelihood estimators of the model parameters are derived and their asymptotic properties are established. The performance of these estimators is compared with the maximum likelihood estimator via simulation. 相似文献
863.
864.
中国的农民工阶层是改革开放以后才出现的。根据公开的统计数据,近年来,农民工流动的规模每年已经超过1亿人。农民工占城市第二、第三产业劳动力的比重很多地方已经超过50%。可以说,农民工已经成为城市第二、第三产业劳动力大军的重要组成部分,农民工对中国国民经济的贡献功不可没。文章利用农业部农村固定观察点的数据,测算了农民工对全国第二、第三产业产值增长的贡献。研究结果表明,1995年至2005年,如果假设农民工劳动生产率与城市产业工人一样,则农民工对中国第二、第三产业产值贡献占到这些产业产值的14.77%~24.35%,平均每年为19.98%;如果假设农民工劳动生产率低于城市产业工人,则农民工对中国第二、第三产业产值贡献占到这些产业产值的1.67%~4.71%,平均每年为3.26%,而且贡献份额有逐年增长的趋势。 相似文献
865.
Terence C. Mills 《Journal of applied statistics》2007,34(8):963-972
This note reconsiders the 'classical' approach to trend estimation and presents a modern treatment of this technique that enables trend filters which incorporate end-effects to be constructed easily and efficiently. The approach is illustrated by estimating recent Northern Hemispheric temperature trends. In so doing, it shows how classical trend models may be selected in empirical applications and indicates how this choice determines the properties of the latest trend estimates. 相似文献
866.
国内删失数据统计研究状况综述 总被引:1,自引:0,他引:1
研究了国内在线性回归模型、非线性回归模型、半参数回归、非参数回归、单指标回归、生存分析、时间序列分析、密度估计等领域删失数据统计研究状况。 相似文献
867.
针对IEEE 802.16无线信道进行了仿真,提出了一种工作于该信道的16QAM突发模式的快速均衡器算法,该算法采用Neuman-Hoffman序列的扩展序列进行信道快速估计,及用均衡器系数预加载算法以提高收敛速度,仿真结果证明:算法收敛速度优于递归最小二乘算法。 相似文献
868.
The scale-up method estimates the size of hard to count subpopulations. This method is based on the idea that the proportion of subjects in a subpopulation E known to each member of the general population T is the same as the proportion of members of E belonging to general population T. 相似文献
869.
In this paper, we consider chain ratio and regression type estimators for estimating median in survey sampling. We find expressions
for the variance of the chain-ratio and chain-regression type estimators considered in the present investigation. The optimum
values of the first phase and second phase sample sizes are also obtained for the fixed cost of survey. The relative efficiency
of chain-ratio and chain-regression type estimators have been studied in comparison to ratio and regression type estimators
of median proposed by Singh, Joarder and Tracy (2001). 相似文献
870.
Although Hartigan (1975) had already put forward the idea of connecting identification of subpopulations with regions with
high density of the underlying probability distribution, the actual development of methods for cluster analysis has largely
shifted towards other directions, for computational convenience. Current computational resources allow us to reconsider this
formulation and to develop clustering techniques directly in order to identify local modes of the density. Given a set of
observations, a nonparametric estimate of the underlying density function is constructed, and subsets of points with high
density are formed through suitable manipulation of the associated Delaunay triangulation. The method is illustrated with
some numerical examples. 相似文献