Estimation of noncentrality parameters

We propose some estimators of noncentrality parameters which improve upon usual unbiased estimators under quadratic loss. The distributions we consider are the noncentral chi-square and the noncentral F. However, we give more general results for the family of elliptically contoured distributions and propose a robust dominating estimator.     

‘I Just Don't Want to Get Picked on by Anybody’: Dynamics of Inclusion and Exclusion in a Newly Multi‐Ethnic Irish Primary School

Given the changing patterns of immigration in the Republic of Ireland in the past 10 years, this article considers how factors related to ethnic and gender identity mediate children's interaction with one another in a newly multi‐ethnic Irish primary school. Central to the analysis is the exercise of power between children and how the experience of inclusion and exclusion in peer relations is underpinned by concepts of sameness/difference that draw upon wider discourses of ethnic and gender identity. Recommendations in relation to classroom and school practice are made with reference to the need for teachers to take account of the complexity of children's social worlds and the dynamics of power and control that operate within it. Copyright © 2006 The Author(s).     

Marginal and association regression models for longitudinal binary data with drop‐outs: A likelihood‐based approach

Longitudinal data often contain missing observations, and it is in general difficult to justify particular missing data mechanisms, whether random or not, that may be hard to distinguish. The authors describe a likelihood‐based approach to estimating both the mean response and association parameters for longitudinal binary data with drop‐outs. They specify marginal and dependence structures as regression models which link the responses to the covariates. They illustrate their approach using a data set from the Waterloo Smoking Prevention Project They also report the results of simulation studies carried out to assess the performance of their technique under various circumstances.     

Estimation of Metabolic Rate Constants in PBPK‐Models from Liver Slice Experiments: What Are the Experimental Needs?

A mechanistic model is presented describing the clearance of a compound in a precision-cut liver slice that is incubated in a culture medium. The problem of estimating metabolic rate constants in PBPK models from liver slice experiments is discussed using identifiability analysis. From the identifiability problem analysis, it appears that in addition to the clearance, the compound's free fraction in the slice and the diffusion rate of the exchange of the compound between culture medium and liver slice should be identified. In addition, knowledge of the culture medium volume, the slice volume, the compound's free fraction, and octanol-water-based partition between medium and slice is presupposed. The formal solution for identification is discussed from the perspective of experimental practice. A formally necessary condition for identification is the sampling of parent compound in liver slice or culture medium. However, due to experimental limitations and errors, sampling the parent compound in the slice together with additional sampling of metabolite pooled from the medium and the slice is required for identification in practice. Moreover, it appears that identification results are unreliable when the value of the intrinsic clearance exceeds the value of the diffusion coefficient, a condition to be verified a posteriori.     

Gender-specific changes in students' sexual behaviors and attitudes at a southeastern university between 1973 and 1988.

This study investigated the gender-specific, self-reported sexual behaviors and attitudes of never-married college students attending a southeastern university in 1973 and 1988. Data were collected by means of a mailed questionnaire that remained essentially unchanged for both years. The authors found that both men and women reported an increase in heterosexual relationships that included sexual intercourse and a decrease in nonsexual relationships with the other gender. The majority of the students perceived themselves as adequately informed about sexuality and satisfied with their relationships, although the proportion of men who reported being satisfied with their relationships declined over the 15 years. The students indicated that sexuality education should focus primarily on information about AIDS and on preparation for marriage.     

Procedures and tables for the construction and selection of chain sampling plans ChSP-4A(c1, c2,)r-Part 4

In this part of the series, the notion of average total inspection (ATI) is introduced to ChSP-4A(c1, c2)r plans, minimizing ATI at a given process average, while protection to the consumer is given in terms of average outgoing quality limit and limiting quality level. The procedure is similar to that of Dodge and Roming.     

Determinants of housing quality: A comparison of white,African-American,and Hispanic single-parent women

This study examines housing quality among three groups of single-parent women: white, African-American, and Hispanic. Three indicators of housing quality—crowding, affordability, and satisfaction—are used to discover the extent to which these groups experience housing problems. This study also explores differences and similarities in the factors that precipitate problems in housing quality for these three groups of single parents. Findings suggest important differences and similarities in the nature of housing quality problems among white, African-American, and Hispanic single-parent women. The specified variables explained about 20% of the variance in crowding, housing affordability, and housing satisfaction. On measures of objective and subjective housing quality, white single mothers are better housed than their African-American or Hispanic counterparts. Hispanic single mothers have the largest housing cost burden and average more persons per household than the other groups. African-Americans are twice as likely as either group to live in low-quality housing and reported the lowest average satisfaction with their housing. Her research interests include housing and neighborhood assessment and women and public policy issues. She has recently published articles inUrban Affairs Quarterly andHousing and Society on housing and neighborhood assessment criteria among black urban households and the housing cost burden of various groups of female-headed households. She received her Ph.D. from Ohio State University. Her research interests include the housing adjustment behavior of women and public policy. She has recently completed her thesis on the role of noncustodial parents in determining the quality of life of their children. She is also the recipient of the Tessie Agan Award for research excellence from the American Association of Housing Educators for a paper titled “Unterstanding Constraints and Residential Satisfaction among Low-Income Single-Parent Families.”