New imperfect rankings models for ranked set sampling

Ranked set sampling is a sampling approach that leads to improved statistical inference in situations where the units to be sampled can be ranked relative to each other prior to formal measurement. This ranking may be done either by subjective judgment or according to an auxiliary variable, and it need not be completely accurate. In fact, results in the literature have shown that no matter how poor the quality of the ranking, procedures based on ranked set sampling tend to be at least as efficient as procedures based on simple random sampling. However, efforts to quantify the gains in efficiency for ranked set sampling procedures have been hampered by a shortage of available models for imperfect rankings. In this paper, we introduce a new class of models for imperfect rankings, and we provide a rigorous proof that essentially any reasonable model for imperfect rankings is a limit of models in this class. We then describe a specific, easily applied method for selecting an appropriate imperfect rankings model from the class.     

Race, Risk, and the Emergence of Gender Boundaries: Kids Crossing Boundaries in Summer Camps

My study explores how children established and crossed gender boundaries in four recreational settings with different racial compositions and patterns. Children generally marked boys' gender boundary crossing as more deviant than girls' crossing. However, the amount of gender salience structured into each setting and the salience of race in each setting affected campers' perceptions of the risks from gender boundary crossing and, thus, their strategies for crossing. My findings suggest that the perceived race of the actor may be less important than the race of the audience. Also crucial are the ways in which race category membership gives meaning to gender boundaries and to gender deviance in a particular situation.     

If you look like me,I'll talk to you: a preliminary study of ethnic identity and inter‐ethnic interaction among women in Singapore

In Singapore, government policy is for equal but separate development of the four major ethnic groups—Chinese, Malay, Indian and other. In this study, I attempt to gain some preliminary views of how strongly women identify with their own ethnic group and how freely they are prepared to interact with people from other ethnic groups in non‐work‐related situations. I confine my study to females for two reasons. One is that traditional ethnic dress is common among females in Singapore but much rarer among men, and this makes a strong non‐verbal statement of identity. The second reason is to avoid differences between males and females, which I did not wish to pursue within the limits of this exploratory study. The findings of my pilot investigation indicate that intra‐ethnic spontaneous interaction is more likely to occur among women who display a strong national identity. Moreover, younger women, who were exposed during their school years to the government's recent drive to nurture ethnic and cultural differences, are less open to inter‐ethnic interaction than are women in their 30s and older, who grew up when the government drive was towards creating one common national identity for the people of Singapore.     

Reducing Refusal Rates for Telephone Interviews

In two experiments, refusal rates to telephone interviews werenot affected by substantial changes in the introductory remarksof the interviewer. A prior letter significantly lowered refusalrates in a third experiment. In all three, interviewer sex hadno effect.     

Early experiences of mentoring: Design and use of multimedia materials for teaching OR/MS

The MENTOR project, based at the University of Strathclyde, is producing multimedia computer based learning materials with the aim of improving both the effectiveness and the efficiency of teaching Operational Research/Management Science in higher education. The process of development has been carefully designed to encourage ownership of and commitment to the materials amongst lecturing staff in Universities, with the aim of ensuring widespread use. The paper outlines this process of development and design of materials. Experiences in introducing students to the use of these materials as an integrated part of a Management Science class are reported. Feedback from students has been very positive but also indicates the need for ongoing support and direction.     

South Africa's 'Rainbow People', National Pride and Happiness

Since the first free elections were held in April 1994, South Africans are popularly known as the 'rainbow people'. The paper inquires whether South Africans who experienced pride in their nation in the first years of democracy also perceived a greater sense of subjective well-being. It is proposed that national pride in post-apartheid South Africa might be fused with or work through self-esteem to lift levels of happiness. The paper traces the history of the new integrating civil religion of the rainbow people and the acceptance of the rainbow as a political symbol of unity among the diverse people of South Africa immediately after the 1994 elections and two years later. The proposed link between national pride and happiness was explored with data from two independent national surveys, the 1995 South African World Values Survey conducted by Markinor and a June 1996 MarkData syndicated omnibus survey. The study found that the appeal of the rainbow as political symbol was inclusive of all groups in society and that feelings of national pride and support for the rainbow ideal were positively associated with subjective well-being. As indicated by intensity and frequency measures, the majority of South Africans were proud of their country and could name a national achievement that inspired pride. Better-off South Africans tended to be happier and more satisfied with life but less proud, while the poor were less happy but fiercely proud of their country. Results suggest that belief in South Africa's 'rainbow nation' ideal may have assisted in boosting happiness during the transition to a stable democracy, thereby preventing alienation among the losers under the new political dispensation. Supporters of the ideal of the rainbow nation were more optimistic than others about the future of their country.     

DETERMINING THE APPROPRIATE DISCOUNT RATES IN PURE CAPITAL RATIONING

This paper proposes an interpretation of the pure capital rationing problem as it is faced by many managers in decentralized firms in which budgets serve as the principal means of control. It is argued that the appropriate objective for situations such as these is the maximization of either undiscounted earnings over the planning horizon or total value of the investments at the horizon. When either objective function is used in conjunction with the frequently encountered linear programming models for the capital rationing problem, shadow prices result which give rise to discount rates that will reproduce the optimal solution using discounted cash flow as a criterion. These results are then used as a means for clarifying several confusing and misleading statements that have appeared in the literature.     

Predictive Inference for Big,Spatial, Non‐Gaussian Data: MODIS Cloud Data and its Change‐of‐Support

Remote sensing of the earth with satellites yields datasets that can be massive in size, nonstationary in space, and non‐Gaussian in distribution. To overcome computational challenges, we use the reduced‐rank spatial random effects (SRE) model in a statistical analysis of cloud‐mask data from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on board NASA's Terra satellite. Parameterisations of cloud processes are the biggest source of uncertainty and sensitivity in different climate models’ future projections of Earth's climate. An accurate quantification of the spatial distribution of clouds, as well as a rigorously estimated pixel‐scale clear‐sky‐probability process, is needed to establish reliable estimates of cloud‐distributional changes and trends caused by climate change. Here we give a hierarchical spatial‐statistical modelling approach for a very large spatial dataset of 2.75 million pixels, corresponding to a granule of MODIS cloud‐mask data, and we use spatial change‐of‐Support relationships to estimate cloud fraction at coarser resolutions. Our model is non‐Gaussian; it postulates a hidden process for the clear‐sky probability that makes use of the SRE model, EM‐estimation, and optimal (empirical Bayes) spatial prediction of the clear‐sky‐probability process. Measures of prediction uncertainty are also given.     

Extending Bayesian back-calculation to estimate age and time specific HIV incidence

Lifetime Data Analysis - CD4-based multi-state back-calculation methods are key for monitoring the HIV epidemic, providing estimates of HIV incidence and diagnosis rates by disentangling their...