Further Results on Order Statistics Generated by Two Simulation Methods

Uniform order statistics generated by two simulation methods are compared by means of Pitman’s measure of closeness. This measure, as a probability, is shown to be asymptotically 1/2. Some results are also established for fixed points of the cumulative distribution function (CDF) for a uniform order statistic. These fixed points are important for calculations involving the joint distribution of these order statistics.     

The family caregiving career: implications for community-based long-term care practice and policy

Informal (i.e., unpaid) long-term care for disabled older adults is often chronic, but it is only recently that research has considered the longitudinal implications of family caregiving. In particular, investigators have conceptualized caregiving as a "career," and within the caregiving career, a number of diverse trajectories and transitions can occur. Following a summary of these findings, this paper considers how longitudinal caregiving research can influence and potentially address key policy and practice concerns, especially in the delivery and support of community-based long-term care (CBLTC) services. It is suggested that with the refinement of the informal long-term care literature, existing policy and practice to support caregiving families can be similarly advanced.     

Relation Between Maternal Cigarette Smoking During Pregnancy and Behavioral and Physiological Measures of Autonomic Regulation in Neonates

The effects of maternal cigarette smoking during pregnancy on behavioral and physiological measures of arousal were examined in a sample of 50 neonates. After the effects of alcohol, caffeine, and maternal demographic variables were statistically controlled, regression analyses showed that maternal smoking during pregnancy was predictive of higher heart rates overall and during quiet and active sleep. Maternal smoking during pregnancy was also predictive of lower heart rate variability and an increased number of tremors and changes in behavioral state. These findings suggest that maternal cigarette smoking during pregnancy affects the regulation of spontaneous autonomic activity in neonates.     

Role sequencing: does order matter for mental health?

Role sequencing refers to the ordering of social roles. According to the normative order hypothesis, adults who follow a certain sequencing of their social roles will be better adjusted than their peers who follow other life course patterns. The normative order is defined as first entering the paid labor force, getting married, and later having children. This study tests this hypothesis by analyzing retrospective life history data from three subsamples of adults who completed the 1987--1988 National Survey of Families and Households: (1) married, working parents; (2) divorced, working parents; and (3) married, unemployed parents. The findings indicate significant race/ethnic (black/white), gender, and cohort differences in the type of role sequencing patterns that are conducive to positive mental health. For example, African Americans who work first, then have children, and later get married report better mental health than their peers who followed the normative order White men and women seem to benefit from following the normative course of role transitions. Among women, however, the psychological benefits of following typical life course patterns are especially evident among those born during the baby boom.     

Ethnicity-of-Interviewer Effects Among Mexican-Americans and Anglos

A general interpersonal deference explanation for ethnicity-of-interviewereffects is tested with a random survey of Anglos and Mexican-Americansusing Anglo and Hispanic interviewers and questions relatedto Mexican-American culture. The theory was most clearly supportedamong Anglo respondents. The mixed support found among Mexican-Americanssuggests that deference is strongest when questions deal withthe culture represented by the interviewer, not the respondent.     

Personality preferences in laboratory economics experiments

Student volunteers at the U.S. Naval Academy (USNA) participated in one of the following one-shot games: a dictator game, an ultimatum game, a trust game, or a prisoner's dilemma game. We find limited support for the importance of personality type for explaining subjects’ decisions. With controls for personality preferences, we find little evidence of behavioral differences between males and females. Furthermore, we conclude that seniority breeds feelings of entitlement—seniors at USNA generally exhibited the least cooperative or other-regarding behavior.     

Vector quantization: clustering and classification trees

An image that is mapped into a bit stream suitable for communication over or storage in a digital medium is said to have been compressed. Using tree-structured vector quantizers (TSVQs) is an approach to image compression in which clustering algorithms are combined with ideas from tree-structured classification to provide code books that can be searched quickly and simply. The overall goal is to optimize the quality of the compressed image subject to a constraint on the communication or storage capacity, i.e. on the allowed bit rate. General goals of image compression and vector quantization are summarized in this paper. There is discussion of methods for code book design, particularly the generalized Lloyd algorithm for clustering, and methods for splitting and pruning that have been extended from the design of classification trees to TSVQs. The resulting codes, called pruned TSVQs, are of variable rate, and yield lower distortion than fixed-rate, full-search vector quantizers for a given average bit rate. They have simple encoders and a natural successive approximation (progressive) property. Applications of pruned TSVQs are discussed, particularly compressing computerized tomography images. In this work, the key issue is not merely the subjective attractiveness of the compressed image but rather whether the diagnostic accuracy is adversely aflected by compression. In recent work, TSVQs have been combined with other types of image processing, including segmentation and enhancement. The relationship between vector quantizer performance and the size of the training sequence used to design the code and other asymptotic properties of the codes are discussed.     

A scientist's viewpoint on promoting effective use of experimental design: Ten things a scientist wants to know about experimental design

This paper tackles the practical application of statistical tools. Chemical development is a rich area for collaboration between statisticians and chemists, but most statisticians encounter difficulties in promoting the tools to this client group. This paper, presented from a chemist's perspective, is intended to help bridge the gap between the two professions. The paper explores differences in uptake and attitudes towards adopting these techniques and suggests what has hindered or helped the process of effective application of experimental design. Copyright © 2003 John Wiley & Sons, Ltd.