Best linear unbiased and invariant estimation in location-scale families based on double-ranked set sampling

Abstract

In this article, we propose the best linear unbiased estimators (BLUEs) and best linear invariant estimators (BLIEs) for the unknown parameters of location-scale family of distributions based on double-ranked set sampling (DRSS) using perfect and imperfect rankings. These estimators are then compared with the BLUEs and BLIEs based on ranked set sampling (RSS). It is shown that under perfect ranking, the proposed estimators are uniformly better than the BLUEs and BLIEs obtained via RSS. We also propose the best linear unbiased quantile (BLUQ) and the best linear invariant quantile (BLIQ) estimators for normal distribution under DRSS. It is observed that the proposed quantile estimators are more efficient than the BLUQ and BLIQ estimators based on RSS for both perfect and imperfect orderings.     

Family influences on adolescent male sexuality: the mediational role of self-restraint

To assess childhood family influences on adolescent sexual activity, 69 boys were studied in sixth grade and again in tenth grade. Boys' self-restraint in sixth grade was hypothesized to mediate the effects of family influences on number of sexual partners four years later. Family scores included observed family interaction patterns, sons' reports of parents' child-rearing practices (rejection, support, child-centered/indulgence), and household composition. In different models, Time 1 family scores and sons' self-restraint accounts for 34 and 48 percent of the variance in sons' subsequent sexuality. As predicted, regression analysis revealed that restraint mediated family influence at Time 1 on the number of sexual partners at Time 2. Notably, intact family, supportive family and child-centred/indulgent parenting were associated with T1 restraint which in turn, was associated with sexual activity. Additionally, family/parenting scores were directly associated with adolescents' sexuality. In discriminant analyses, family scores predicted boys' status as virgins/nonvirgins four year later with greater than 70% success. Discussion focuses on the nature of the family influences and the mechanisms by which they relate to adolescent male sexuality.     

WHO BUYS HEALTH INSURANCE? A SURVEY OF TWO LARGE ORGANISATIONS

Despite the importance of private insurance in the financing of Australia's health care system, there have been few studies of health insurance choice. A survey was carried out of employees of two large organisations to serve as a reference group for middle-income people in secure employment. Insurance was associated with income, age, marital status and history of medical costs; but not dependents or hospital expenses. Main determinants of level of cover were income and medical costs. In making decisions, information search was low and decisions seem to be made on the basis of simple risk aversion, influenced by insurers' advertising.     

Improving judgment by reconciling incoherence

This paper discusses how a subject's judgments about his actions, uncertainties and values may be improved by seeking out and reconciling inconsistences between related judgments. Decision theory tells us that there are relationships between coherent judgments, such as between a prior, likelihood and posterior, but does not tell us how a subject is to reconcile his own, possibly incoherent, views. The role of coherence in improving judgments is not clear. This paper discusses whether there is a unique, best reconciliation of incoherent judgments and how such reconciliation could improve decision-making. The basic principles of the coherent view are explained and a language developed in which the problem of reconciliation can be discussed. The practical importance of the problem is emphasized, illustrated by several examples and possible solutions are explored.     

Students' of Color and European American Students' Stigma-Relevant Perceptions of University Instructors

In classrooms students of color may experience stigma (i.e., concern about being stereotyped) because negative stereotypes of their intellect are salient. Two studies included African American, European American, and Latina/Latino female and male undergraduates. Study 1 ( n = 86) demonstrated while students of color generally had positive expectations of teachers, their expectations declined when imagining class with a European American instructor who would repeatedly versus never evaluate their work or an ethnically matched instructor across conditions. Study 2 ( n = 136) revealed all students had more positive expectations of culturally tolerant versus culturally intolerant instructors. Students of color more than European American students perceived that intolerant instructors could grade them unfairly. We discuss implications for ethnically diverse classrooms .