Improved best linear unbiased estimators for the simple linear regression model using double ranked set sampling schemes

ABSTRACT

In this paper, we consider the best linear unbiased estimators (BLUEs) based on double ranked set sampling (DRSS) and ordered DRSS (ODRSS) schemes for the simple linear regression model with replicated observations. We assume three symmetric distributions for the random error term, i.e., normal, Laplace and some scale contaminated normal distributions. The proposed BLUEs under DRSS (BLUEs-DRSS) and ODRSS (BLUEs-ODRSS) are compared with the BLUEs based on ordered simple random sampling (OSRS), ranked set sampling (RSS), and ordered RSS (ORSS) schemes. These estimators are compared in terms of relative efficiency (RE), RE of determinant (RED), and RE of trace (RET). It is found that the BLUEs-ODRSS are uniformly better than the BLUEs based on OSRS, RSS, ORSS, and DRSS schemes. We also compare the estimators based on imperfect RSS (IRSS) schemes. It is worth mentioning here that the BLUEs under ordered imperfect DRSS (OIDRSS) are better than their counterparts based on IRSS, ordered IRSS (OIRSS), and imperfect DRSS (IDRSS) methods. Moreover, for sensitivity analysis of the BLUEs, we calculate REs and REDs of the BLUEs under the assumption of normality when in fact the parent distribution follows a non normal symmetric distribution. It turns out that even under violation of normality assumptions, BLUEs of the intercept and the slope parameters are found to be unbiased with equal REs under each sampling scheme. It is also observed that the BLUEs under ODRSS are more efficient than the existing BLUEs.     

Causes and Consequences of the Divergent Working-Time Patterns of Employed Mothers in the UK and the US: Developing a Comparative Analysis

The paper aims to develop a framework to understand the variant use of part-time work by employed mothers in the UK and US. In particular, this paper seeks to explore how diversity in the use of part-time work can be explained when both countries are associated with a neo-liberal form of capitalism (Hall and Soskice, Varieties of Capitalism: the institutional foundations of comparative advantage, 2001) and welfare regime (Esping-Andersen, The three worlds of welfare capitalism, 1990). It is argued here that by combining aspects of the Varieties of Capitalism (VoC) and welfare regimes literatures with Gender Regime theory (Walby, Social Politics, 11(1):4–29, 2004), a gender centred analysis of both the causes and consequences of divergent working-time patterns can be more adequately achieved.

Reciprocal relationships between attitudes about gender and social contexts during young adulthood

Using data from a 31-year panel study, we investigate reciprocal relationships between individuals’ attitudes about gender and their experience with a range of social settings commonly associated with the transition to adulthood. These settings include school, the labor market, independent living arrangements, cohabitation, marriage, and parenthood. We consider the extent to which gender and age moderate the relationships between attitudes about gender and exposure to these social contexts. Ordinary least squares regression and hazard models demonstrate that support for egalitarian roles for women and men in families is positively linked to subsequent school enrollment, women’s full-time employment, and independent living, but negatively associated with the subsequent timing of entry into marriage and marital parenthood. Accumulated schooling, independent living, and full-time employment are associated with changes in individuals’ attitudes about gender. Despite careful attention to gender differences, we find surprisingly little evidence that the causes and consequences of attitudes about gender differ for women and men, with the primary exception being the positive association of employment and egalitarian gender attitudes for women but not for men.     

A comparison of estimators for regression models with change points

We consider two problems concerning locating change points in a linear regression model. One involves jump discontinuities (change-point) in a regression model and the other involves regression lines connected at unknown points. We compare four methods for estimating single or multiple change points in a regression model, when both the error variance and regression coefficients change simultaneously at the unknown point(s): Bayesian, Julious, grid search, and the segmented methods. The proposed methods are evaluated via a simulation study and compared via some standard measures of estimation bias and precision. Finally, the methods are illustrated and compared using three real data sets. The simulation and empirical results overall favor both the segmented and Bayesian methods of estimation, which simultaneously estimate the change point and the other model parameters, though only the Bayesian method is able to handle both continuous and dis-continuous change point problems successfully. If it is known that regression lines are continuous then the segmented method ranked first among methods.     

结构紧凑操作简便的倒置式荧光显微镜的应用

介绍了来自于首批LumaScoe倒置式荧光显微镜使用者在美国不同研究实验室、教学实验室、病人检查室及家庭客厅等处采集到的不同样品的新近图像。     

Neighborhood affluence protects against antenatal smoking: Evidence from a spatial multiple membership model

ABSTRACT

A spatial multiple membership model formalizes the effect of neighborhood affluence on antenatal smoking. The data are geocoded New Jersey birth certificate records linked to United States census tract-level data from 1999 to 2007. Neighborhood affluence shows significant spatial autocorrelation and local clustering. Better model fit is observed when incorporating the spatial clustering of neighborhood affluence into multivariate analyses. Relative to the spatial multiple membership model, the multilevel model that ignores spatial clustering produced downwardly biased standard errors; the effective sample size of the key parameter of interest (neighborhood affluence) is also lower. Residents of communities located in high-high affluence clusters likely have better access to health-promoting institutions that regulate antenatal smoking behaviors.     

Reports of Conferences,Institutes, and Seminars

Abstract

This column includes reports on sessions from the Electronic Resources Minnesota Conference 2019 and Charleston Library Conference 2019. The reports cover a user experience analysis of a discovery system, managing change due to an organizational restructure, improving communication between subject specialists and technical services, and key findings of the LYRASIS 2019 Accessibility Survey Report.     

Was pet relinquishment related to foreclosure?: A spatial research note from California during the height of foreclosure

Media reports asserted that the 2008 foreclosure crisis unleashed a rash of pet relinquishments, especially in California's central valley, an area that had the highest U.S. foreclosure rates that year. However, reports on the foreclosure/relinquishment association relied on anecdotal evidence provided by animal shelters, which is known to be flawed since many people do not give a reason for relinquishment, or give a false reason. This study compares separate data sources for the central valley city of Turlock, 2008: foreclosure data from the Stanislaus County Recorder's Office (N = 235) and relinquishment data from the Turlock Animal Shelter (N = 248). Contrary to shelter driven data, these separate data sources reported only one shared address. However, spatial analyses show that foreclosures and relinquishments were concentrated in similar areas. Analyses also show that unaltered (non-spayed/neutered) dogs are more likely to be concentrated in lower socioeconomic (SES) areas. While our initial finding contradicts recent media reports, spatial analyses verify other research on the social problems associated with concentrated foreclosures, and lend support for policies designed to reduce breeding during heighted periods of foreclosure and other economic crises.     

Relationship Characteristics and the Relationship Context of Nonmarital First Births Among Young Adult Women

OBJECTIVES: The objectives of this study were to examine whether and how characteristics of the relationship dyad are linked to nonmarital childbearing among young adult women, additionally distinguishing between cohabiting and nonunion births. METHODS: We used the National Longitudinal Survey of Youth, 1997 Cohort and discrete-time event history methods to examine these objectives. RESULTS: Our analyses found that similarities and differences between women and their most recent sexual partner in educational attainment, disengagement from work or school, race/ethnicity, and age were linked to the risk and context of nonmarital childbearing. For example, partner disengagement (from school and work) was associated with increased odds of a nonmarital birth regardless of whether the woman herself was disengaged. Additionally, having a partner of a different race/ethnicity was associated with nonmarital childbearing for whites, but not for blacks and Hispanics. CONCLUSIONS: We conclude that relationship characteristics are an important dimension of the lives of young adults that influence their odds of having a birth outside of marriage.