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81.
BIAS IN LIST-ASSISTED TELEPHONE SAMPLES 总被引:4,自引:1,他引:3
BRICK J. MICHAEL; WAKSBERG JOSEPH; KULP DALE; STARER AMY 《Public opinion quarterly》1995,59(2):218-235
A number of researchers have suggested list-assisted samplingfor the selection of telephone households to overcome some ofthe operational difficulties associated with the Mitofsky-Waksbergmethods of random digit dialing (RDD). An advantage of a list-assistedmethod of RDD is that an equal probability systematic sampleof telephone numbers can be selected and the variances of estimatesfrom such a sample are usually lower than from a clustered designlike the Mitofsky-Waksberg method. The main disadvantage ofthe list-assisted method is that it excludes some householdsfrom the sample, thus creating a coverage bias in the estimates.This article describes research on the coverage bias for a particularmethod of list-assisted sampling. The two key determinants ofcoverage bias are the proportion of households that are noteligible for the sample and the differences in the characteristicsof the covered and not covered populations. The results showthat about 4 percent of all households are excluded in nationalsamples using this method of sampling. Furthermore, they showthat the differences between the covered and uncovered populationsare generally not large. The coverage bias resulting from theseconditions may often be small. 相似文献
82.
Albert A. Bartlett 《Population and environment》1993,14(4):359-387
This is a tutorial on the relations between population data and the rates of growth that are calculated from the data. For the calculation of rates of growth, discrete and continuous compounding will be compared so that the reader can see the reasons for using the mathematics of continuous compounding, which is the mathematics of exponential growth. Some properties of exponential growth are developed. Semi-logarithmic graphs will be discussed as a device for representing the size of growing populations and for analyzing the nature of the growth. Illustrative examples will be worked out in order to emphasize applications and utility. 相似文献
83.
本文报道了在LRH-250E型培养箱中对平均尾重0.2g和1.2g的虎鲨进行温度耐受性试验,并对均重1.2g的虎鲨做了pH耐受性研究。结果表明:尾重O.2g的虎鲨在驯化温度为20℃时,水温突变引起的致死高温为41℃,致死低温为14℃;尾重1.2g虎鲨在驯化温度为24℃时,水温突变引起的致死高温是42℃,致死低温为14.5℃。尾重1.2g虎鲨能够耐受的pH值其上限是11.51,下限是2.52。 相似文献
84.
长期以来 ,我国高等教育存在的最突出、最根本的问题是投入问题。无论是宏观背景从计划体制到市场化改革 ,还是从控制规模的精英教育到连续扩招的大众化推进 ,包括高校收费制度改革 ,我国高等教育投入和经费困扰的基本状况没有重大改变 ,这种现象长期化存在本身 ,表明高等教育的投入严重不足问题 ,不应仅仅归结为“财政压力”和认识问题。客观上 ,这种机制障碍 ,已经成为一种制度性约束。作者在我国已经连续五年实施积极财政政策的背景下 ,从改善和扩大供给的角度 ,探讨在根本解决高等教育投入不足的公共财政体制性改革之前 ,运用作为非正式制度变迁手段的财政政策 ,面对加入WTO后的高等教育国际竞争挑战 ,利用国债资金 ,调整支出结构 ,阶段性、分层次、集中加大对高等教育的公共财政投入 ,全方位改善高等教育的长期供给 ,拉动消费需求 ,促进经济增长 相似文献
85.
设计多媒体课件 ,要了解授课对象的基本情况 ,根据教学目标选定教学内容。在各学习界面的设计中 ,充分体现教学策略 相似文献
86.
Multiparameter evidence synthesis in epidemiology and medical decision-making: current approaches 总被引:1,自引:0,他引:1
A. E. Ades A. J. Sutton 《Journal of the Royal Statistical Society. Series A, (Statistics in Society)》2006,169(1):5-35
Summary. Alongside the development of meta-analysis as a tool for summarizing research literature, there is renewed interest in broader forms of quantitative synthesis that are aimed at combining evidence from different study designs or evidence on multiple parameters. These have been proposed under various headings: the confidence profile method, cross-design synthesis, hierarchical models and generalized evidence synthesis. Models that are used in health technology assessment are also referred to as representing a synthesis of evidence in a mathematical structure. Here we review alternative approaches to statistical evidence synthesis, and their implications for epidemiology and medical decision-making. The methods include hierarchical models, models informed by evidence on different functions of several parameters and models incorporating both of these features. The need to check for consistency of evidence when using these powerful methods is emphasized. We develop a rationale for evidence synthesis that is based on Bayesian decision modelling and expected value of information theory, which stresses not only the need for a lack of bias in estimates of treatment effects but also a lack of bias in assessments of uncertainty. The increasing reliance of governmental bodies like the UK National Institute for Clinical Excellence on complex evidence synthesis in decision modelling is discussed. 相似文献
87.
目前法院以民事审判方式解决与社会保险费用征缴相关的劳动争议,并不是一个有益的救济方式;劳动保障部门或税务机关依照《社会保险费征缴暂行条例》以具体行政行为的方式给予保障才是高效、便捷、法律依据充分的途径。相关当事人对该行政行为的合法性如有异议,亦可按行政诉讼的途径给予救济。制度的设立、完善与落实是根本,行政诉讼是制度实现的保障,民事诉讼的介入则会对社会保险制度的完善和发展产生抑制作用 相似文献
88.
Herein, we propose a data-driven test that assesses the lack of fit of nonlinear regression models. The comparison of local linear kernel and parametric fits is the basis of this test, and specific boundary-corrected kernels are not needed at the boundary when local linear fitting is used. Under the parametric null model, the asymptotically optimal bandwidth can be used for bandwidth selection. This selection method leads to the data-driven test that has a limiting normal distribution under the null hypothesis and is consistent against any fixed alternative. The finite-sample property of the proposed data-driven test is illustrated, and the power of the test is compared with that of some existing tests via simulation studies. We illustrate the practicality of the proposed test by using two data sets. 相似文献
89.
思维方式对语言的结构有哪些影响?本文从形合与意合在句法上与章法上的不同表现,论述了英汉两种语言在结构和表达方式上的不同,并通过实例归纳出一些具体做法,供同行进一步探讨。 相似文献
90.
Ruth V. Aguilera 《英国管理杂志》2005,16(Z1):S39-S53
This paper examines the role of boards of directors in light of institutional contingencies and recent best practice governance guidelines and regulation such as the United Kingdom Higgs Review and the United States Sarbanes‐Oxley Act 2002. Particular attention is paid to discussing the role of independent directors across countries, and the implications for corporate governance innovation. It concludes by posing questions about recent corporate governance transformations and providing suggestions for future research. 相似文献