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41.
基于西部3省731户农(牧)户的实地调研数据,从农(牧)户劳动力配置视角分析了牧地承包经营权转让意愿的影响因素。研究结果表明:务牧人口数、近三年务牧消耗、务牧技能水平等对牧地承包经营权转出意愿有显著的负向影响;务工兼牧业人口数、务工技能水平和户均单位土地劳动投入对牧地承包经营权转出意愿有显著的正向影响;务工人口数、户主受教育程度等对牧地承包经营权转让意愿的影响不显著。 相似文献
42.
Copula-based regression models: A survey 总被引:1,自引:0,他引:1
In this review paper we collect several results about copula-based models, especially concerning regression models, by focusing on some insurance applications. 相似文献
43.
Lili Tian Albert Vexler Li Yan Enrique F. Schisterman 《Journal of statistical planning and inference》2009
In many diagnostic studies, multiple diagnostic tests are performed on each subject or multiple disease markers are available. Commonly, the information should be combined to improve the diagnostic accuracy. We consider the problem of comparing the discriminatory abilities between two groups of biomarkers. Specifically, this article focuses on confidence interval estimation of the difference between paired AUCs based on optimally combined markers under the assumption of multivariate normality. Simulation studies demonstrate that the proposed generalized variable approach provides confidence intervals with satisfying coverage probabilities at finite sample sizes. The proposed method can also easily provide P-values for hypothesis testing. Application to analysis of a subset of data from a study on coronary heart disease illustrates the utility of the method in practice. 相似文献
44.
Edwin M. M. Ortega Fernanda B. Rizzato Clarice G. B. Demétrio 《Statistical Methods and Applications》2009,18(3):305-331
In a sample of censored survival times, the presence of an immune proportion of individuals who are not subject to death,
failure or relapse, may be indicated by a relatively high number of individuals with large censored survival times. In this
paper the generalized log-gamma model is modified for the possibility that long-term survivors may be present in the data.
The model attempts to separately estimate the effects of covariates on the surviving fraction, that is, the proportion of
the population for which the event never occurs. The logistic function is used for the regression model of the surviving fraction.
Inference for the model parameters is considered via maximum likelihood. Some influence methods, such as the local influence
and total local influence of an individual are derived, analyzed and discussed. Finally, a data set from the medical area
is analyzed under the log-gamma generalized mixture model. A residual analysis is performed in order to select an appropriate
model.
The authors would like to thank the editor and referees for their helpful comments. This work was supported by CNPq, Brazil. 相似文献
45.
This paper applies stratified random sampling using Neyman allocation to Mangat et al. (1992) unrelated question randomized response (RR) strategy for both completely truthful reporting and less than completely truthful reporting. It is shown that, for the prior information given, our new model is more efficient in terms of variance (in the case of completely truthful reporting) and mean square error (in terms of less than completely truthful reporting) than Kim and Elam's (2007) model. Numerical illustrations and graphs are also given in support of the present study. 相似文献
46.
The crux of this article is to estimate the mean of the number of persons possessing a rare sensitive attribute based on the Mangat (1991) randomization device by utilizing the Poisson distribution in simple random sampling and stratified sampling. Properties of the proposed randomized response (RR) model have been studied along with recommendations. It is also shown that the proposed model is more efficient than that of Land et al. (2011) in simple random sampling and that of Lee et al. (2013) in stratified random sampling when the proportion of persons possessing a rare unrelated attribute is known. Numerical illustrations are also given in support of the present study. 相似文献
47.
L. Ramprasath 《统计学通讯:理论与方法》2017,46(15):7612-7620
This article discusses the role played by stylized features of financial time series in constructing better estimators for the model parameters. We study in detail one such estimator for the transition probabilities of a simple regime switching model. The estimator is based on the squared autocovariances of the time series, which has been discussed in several empirical studies of economic and financial time series. The effectiveness of this estimator in improving the estimation accuracy is investigated, using both finite sample and asymptotic computations. We also report simulation results to confirm our findings and to extend our conclusions over a bigger region of the parameter space. 相似文献
48.
49.
Sandy M. Zgheib Mohammad Kacim Karel Kostev 《Women and birth : journal of the Australian College of Midwives》2017,30(6):e265-e271
Background
During the last decades, there has been an alarming and dramatic increase in the number of cesarean births in both developed and undeveloped countries. This increase has not been clinically justified but, nevertheless, has raised an important number of issues.Aim
The aim of this study was to determine the risk factors associated with the high cesarean section rates in Lebanon.Methods
This study is based on a sample of 29,270 Lebanese women who were pregnant between 2000 and 2015. Among these, 14,327 gave birth by cesarean section and 14,943 gave birth vaginally. To identify the risk factors of cesarean section, logistic regression was applied as a statistical method using the SPSS statistical package.Findings
Of the 29,270 pregnant women included in the study, 49% had cesarean sections while 51% gave birth vaginally. Repeat cesarean section accounted for 23% while vaginal birth after cesarean accounted for only 0.2% of deliveries. In addition, weekdays were associated with a preference of providers to carry out more cesarean sections. According to an analysis of our data using logistic regression, the risk factors associated with the increase in cesarean section rates were advanced maternal age, elective cesarean section, malpresentation of fetus, multiple birth, prolonged pregnancy, prolonged labor, and fetal distress.Conclusion
Based on these results, it is recommended that a new health policy be implemented to reduce the number of unnecessary cesarean deliveries in Lebanon. 相似文献50.
本文基于1990—2013年省际面板数据,以老年人口比重作为老龄化指标,采用基尼系数分解方法和Kernel密度估计方法,实证分析了中国人口老龄化的地区差异及其动态演进过程。研究结果表明:中国人口老龄化在地区分布上呈现出明显的非均衡特征;基尼系数测算及其分解结果表明,人口老龄化的地区差异总体上呈现波动缩小趋势;2004年以前,地区间差距和超变密度交替成为总体地区差异的主要来源,2004年以后,超变密度成为总体差异的主要来源。 Kernel密度估计显示,老龄化程度不断加深,地区差异呈波动趋势。 相似文献