What is child care? Lessons from time-use surveys of major English-speaking countries

This paper examines the definition and measurement of time devoted to child care in the diary-based surveys administered by the United States, Canada, Australia, and Great Britain. Detailed analysis of the relationship between measures of care activity and supervisory care in the American Time Use Survey (ATUS) illustrate the larger conceptual issues at stake.

对建国以来我国《小学生守则》的回顾与反思

建国以来我国已经五次颁布了《小学生守则》,《小学生守则》的内容随着时代与社会的进步有了长足的发展,但目前由于《小学生守则》在内容、培养目标上的政治化、理想化与成人化,在培养方式上推行知识性的灌输学习,使得《小学生守则》在具体实践上问题重重,其对小学生的素质培养与道德教育没有起到应有的作用。《小学生守则》如何回归生活,如何促进小学生的养成教育应是其今后发展的重点。     

“H型”高血压临床药物联合干预疗效的研究

目的通过观察非洛地平、卡托普利、叶酸及B族维生素联合干预"H型"高血压患者血压、颈动脉内膜中层厚度(CAIMT)及血清同型半胱氨酸(HCY)水平变化,探讨药物联合干预"H型"高血压的临床疗效。方法对86例"H型"高血压患者实施非洛地平、卡托普利、叶酸及B族维生素联合干预8周,对比分析干预前后血压、CAIMT及血清HCY水平变化。结果患者组干预前收缩压(SBP)、舒张压(DBP)、CAIMT及血清HCY水平(168.9±10.4,92.5±11.3,24.7±5.3,0.98±0.19)均显著高于对照组(123.5±6.6,71.8±7.9,9.8±2.7,0.57±0.14)(P0.01),干预后SBP、DBP、CAIMT及血清HCY水平(130.2±8.9,78.7±8.6,10.9±4.2,0.76±0.13)均显著低于干预前(P0.01)。药物联合干预"H型"高血压患者的总有效率为94.2%(81/86)。结论非洛地平、卡托普利、叶酸及B族维生素联合干预"H型"高血压患者,可显著改善血压、颈动脉粥样硬化及血液HCY水平,临床疗效显著。     

在线购物背景下的顾客满意过程

为辨识电子商务时代顾客满意的机制,从整体在线购物体验的视角,开发了一个三阶段的顾客满意过程模型。研究表明：在线购物背景下,满意是顾客历经各个购买阶段的体验的结果;每个阶段的满意度既取决于那个阶段的购物体验,也取决于前面阶段的满意程度;前一阶段的满意将影响后面阶段的满意,它们联合起来形成了整体满意。不同类别的在线顾客之间在顾客满意程度上存在着显著差异。     

Selection and combination of biomarkers using ROC method for disease classification and prediction

Based on the SCAD penalty and the area under the ROC curve (AUC), we propose a new method for selecting and combining biomarkers for disease classification and prediction. The proposed estimator for the combination of the biomarkers has an oracle property; that is, the estimated combination of the biomarkers performs as well as it would have been if the biomarkers significantly associated with the outcome had been known in advance, in terms of discriminative power. The proposed estimator is computationally feasible, n^1/2‐consistent and asymptotically normal. Simulation studies show that the proposed method performs better than existing methods. We illustrate the proposed methodology in the acoustic startle response study. The Canadian Journal of Statistics 39: 324–343; 2011 © 2011 Statistical Society of Canada     

Relative risk regression for current status data in case‐cohort studies

We propose using the weighted likelihood method to fit a general relative risk regression model for the current status data with missing data as arise, for example, in case‐cohort studies. The missingness probability is either known or can be reasonably estimated. Asymptotic properties of the weighted likelihood estimators are established. For the case of using estimated weights, we construct a general theorem that guarantees the asymptotic normality of the M‐estimator of a finite dimensional parameter in a class of semiparametric models, where the infinite dimensional parameter is allowed to converge at a slower than parametric rate, and some other parameters in the objective function are estimated a priori. The weighted bootstrap method is employed to estimate the variances. Simulations show that the proposed method works well for finite sample sizes. A motivating example of the case‐cohort study from an HIV vaccine trial is used to demonstrate the proposed method. The Canadian Journal of Statistics 39: 557–577; 2011. © 2011 Statistical Society of Canada     

Comparison of k independent,zero‐heavy lognormal distributions

Lachenbruch ( 1976 , 2001 ) introduced two‐part tests for comparison of two means in zero‐inflated continuous data. We are extending this approach and compare k independent distributions (by comparing their means, either overall or the departure from equal proportion of zeros and equal means of nonzero values) by introducing two tests: a two‐part Wald test and a two‐part likelihood ratio test. If the continuous part of the distributions is lognormal then the proposed two test statistics have asymptotically chi‐square distribution with $2(k-1)$ degrees of freedom. A simulation study was conducted to compare the performance of the proposed tests with several well‐known tests such as ANOVA, Welch ( 1951 ), Brown & Forsythe ( 1974 ), Kruskal–Wallis, and one‐part Wald test proposed by Tu & Zhou ( 1999 ). Results indicate that the proposed tests keep the nominal type I error and have consistently best power among all tests being compared. An application to rainfall data is provided as an example. The Canadian Journal of Statistics 39: 690–702; 2011. © 2011 Statistical Society of Canada     

A domain outlier robust design and smooth estimation approach

Outliers that commonly occur in business sample surveys can have large impacts on domain estimates. The authors consider an outlier‐robust design and smooth estimation approach, which can be related to the so‐called “Surprise stratum” technique [Kish, “Survey Sampling,” Wiley, New York (1965)]. The sampling design utilizes a threshold sample consisting of previously observed outliers that are selected with probability one, together with stratified simple random sampling from the rest of the population. The domain predictor is an extension of the Winsorization‐based estimator proposed by Rivest and Hidiroglou [Rivest and Hidiroglou, “Outlier Treatment for Disaggregated Estimates,” in “Proceedings of the Section on Survey Research Methods,” American Statistical Association (2004), pp. 4248–4256], and is similar to the estimator for skewed populations suggested by Fuller [Fuller, Statistica Sinica 1991;1:137–158]. It makes use of a domain Winsorized sample mean plus a domain‐specific adjustment of the estimated overall mean of the excess values on top of that. The methods are studied in theory from a design‐based perspective and by simulations based on the Norwegian Research and Development Survey data. Guidelines for choosing the threshold values are provided. The Canadian Journal of Statistics 39: 147–164; 2011 © 2010 Statistical Society of Canada