Random errors in egocentric networks

The systematic errors that are induced by a combination of human memory limitations and common survey design and implementation have long been studied in the context of egocentric networks. Despite this, little if any work exists in the area of random error analysis on these same networks; this paper offers a perspective on the effects of random errors on egonet analysis, as well as the effects of using egonet measures as independent predictors in linear models. We explore the effects of false-positive and false-negative error in egocentric networks on both standard network measures and on linear models through simulation analysis on a ground truth egocentric network sample based on facebook-friendships. Results show that 5–20% error rates, which are consistent with error rates known to occur in ego network data, can cause serious misestimation of network properties and regression parameters.     

Ridge estimation of restricted parameters in production techniques

The problem of determining ridge estimates of the regression parameters in a two-input production function model,constrained to be non-negative,has been formulated as an exercise in quadratic programming. Relevant Kuhn-Tucker conditions have been derived and a small simulation studv has been carried out.     

An Empirical Comparison of Estimating Methods for the Ramberg–Osgood EIV Model

The standard tensile test is one of the most frequent tools performed for the evaluation of mechanical properties of metals. An empirical model proposed by Ramberg and Osgood fits the tensile test data using a nonlinear model for the strain in terms of the stress. It is an Error-In-Variables (EIV) model because of the uncertainty affecting both strain and stress measurement instruments. The SIMEX, a simulation-based method for the estimation of model parameters, is powerful in order to reduce bias due to the measurement error in EIV models. The plan of this article is the following. In Sec. 2, we introduce the Ramberg–Osgood model and another reparametrization according to different assumptions on the independent variable. In Sec. 3, there is a summary of SIMEX method for the case at hand. Section 4 is a comparison between SIMEX and others estimating methods in order to highlight the peculiarities of the different approaches. In the last section, there are some concluding remarks.     

Pooled Cross-Sectional and Time Series Data: A Survey of Current Statistical Methodology

A data base that provides a multivariate statistical history for each of a number of individual entities is called a pooled cross-sectional and time series data base in the econometrics literature. In marketing and survey literature the terms panel data or longitudinal data are often used. In management science a convenient term might be management data base. Such a data base provides a particularly rich environment for statistical analysis. This article reviews methods for estimating multivariate relationships particular to each individual entity and for summarizing these relationships for a number of individuals. Inference to a larger population when the data base is viewed as a sample is also considered.     

中国育龄妇女生育集中度变化分析——基于“五普”、“六普”数据

新中国成立以来,结束了上千年的封建制度给妇女带来的桎梏,妇女的社会地位有了明显的提升,具体表现在社会活动的参与率有了显著的提高,同时妇女在生育行为方面也发生了巨大的变化。本文利用最近两次中国人口普查数据来分析育龄妇女的生育集中度变化情况,并以此对中国目前TFR很低的现象做了解释,据此推断中国在未来几年的时间,总和生育率在一定程度上会呈上升的变化趋势,但不可能在短期内回升到更替水平。     

Optimal estimation of a finite population mean under generalized random permutation models

Employing certain generalized random permutation models and a general class of linear estimators of a finite population mean, it is shown that many of the conventional estimators are “optimal” in the sense of minimum average mean square error. Simple proofs are provided by using a well-known theorem on UMV estimation. The results also cover certain simple response error situations.     

Procedures for improving the mle for ordered binomial parameters

The problem is that of estimating the probabilities of m independent binomial random variables when their probabilities are known to be nondecreasing and the loss function is squared error. In the cases where the m.l.e. is inadmissible (essentially when the total number of trials is 7 or more) we present a method for modifying the m.l.e. to get a better estimator. The method requires a series of changes. At each step we alter the action taken by the m.l.e. on each of three, appropriately chosen, points in the sample space.     

A class of Shrunken estimators for normal mean

This paper presents a class of estimators for the mean of a normal population and determines the conditions on characterizing scalars under which the class of estimators uniformly dominates over the conventional sample mean according to the mean-square-error criterion.     

宋蔡忠惠公书艺书学举要及其现实意义

作为北宋四大书法家之一的蔡襄,以其真、行、草书皆优且概入妙品或精品而卓冠一时,并以其高尚的人品和书品而被誉为"当时第一"。蔡襄的书法风格以平和温厚为主,端庄严整而不刻板,温厚平和而不抵触。其论书标举"神气",反对奇诡失正,追求奇特。蔡襄通过自己的书法实践,不仅改变了宋初书坛的一片靡弱风气,而且使后人能在晋韵唐风中找到书法创作的依据,为书法史的发展注入了新的活力。     

南京市失业人口状况分析

根据"五普"南京市人口10%抽样调查数据,对南京市失业人口状况作了统计分析.分析结果表明,失业人口约占"非在业人口"的1/10略多,其中近2/3为"寻求再就业"人员.人口抽样失业率为6.08%,城区失业率较高,老城区人口失业问题更严重.15～25岁初次寻求就业和40～45岁寻求再就业的群体为两个"就业困难年龄段".女性群体在就业上处于明显弱势,其中25～45岁女性失业比例显著高于男性.但在初次寻找工作中,年轻男性碰到的困难大于年轻女性,而在失业后寻求再就业过程中,女性的困难远高于男性.