A monte carlo of plotting positions

A Monte Carlo study was made of the effects of using simple linear regression, on the appropriate probability paper, to estimate parameters, quantiles and cumulative probability for several distributions. These distributions were the Normal, Weibull (shape parameters 1, 2, and 4) and the Type I largest extreme-value distributions. The specific objective was to observe differences arising from choice of plotting positions. Plotting positions used were i/(n+l), (i?3)/(n+.04), (i?.5)/n, either (i?.375)/(n+.25) or (i?.4)/(n+.2), and either F[E(Y_i)] or F[E(£n Y)]. For each combination of 4 sample sizes (n=10(10)(40)), distribution, and plotting position, regression lines were found for each of N =9999 samples. Each regression line was used to estimate: (1) quantiles of 9 specific probabilities, (2) probabilities of 9 specific quantiles, and (3) return periods corresponding to 9 specific quantiles. Compa[rgrave]ison of the mean, variances, mean square error and medians of these estimates and of the regression coefficients confirm some results of Harter [Commun. Statist. A13(13), 1984] and provide further insight.     

Classification with discrete and continuous variables via general mixed-data models

We study the problem of classifying an individual into one of several populations based on mixed nominal, continuous, and ordinal data. Specifically, we obtain a classification procedure as an extension to the so-called location linear discriminant function, by specifying a general mixed-data model for the joint distribution of the mixed discrete and continuous variables. We outline methods for estimating misclassification error rates. Results of simulations of the performance of proposed classification rules in various settings vis-à-vis a robust mixed-data discrimination method are reported as well. We give an example utilizing data on croup in children.     

Communicating Under Section 112(r) of the Clean Air Act Amendments

Regulations under Section 112(r) of the 1990 Clean Air Act Amendments require fixed facilities having threshold quantities of materials on the U.S. Environmental Protection Agency's list of regulated substances to disclose to the general public the expected offsite consequences of worst-case accidental chemical releases. This paper describes the communication practices of small firms in Delaware and New Jersey and the practical problems these facilities might encounter complying with the proposed rule. The paper reports an interesting difference between the apprehension voiced by small firms required to report worst-case release information and the public's apparent lack of interest in such information. Unlike the difficulty expected by small firms in calculating and communicating worst-case chemical release information, this paper includes some observations on the ability of large chemical firms to comply with the proposed requirements.     

Identifying Dangerous Trucking Firms

The paper develops a statistical procedure for predicting the safety performance of motor carriers based on characteristics of firms and results of two government safety enforcement programs. One program is an audit of management safety practices, and the other is a program to inspect drivers and vehicles at the roadside for compliance with safety regulations. The technique can be used to provide safety regulators with an empirical approach to identify the most dangerous firms and provide a priority list of firms against which educational and enforcement actions should be initiated. The government needs to use such an approach rather than directly observing accident rates because the most dangerous firms are generally small and, despite relatively high accident rates, accidents remain rare events. The technique uses negative-binomial regression procedures on a dataset of 20,000 firms. The definition of poor performance in roadside inspection is based on both the rate of inspections per fleet mile and the average number of violations found during an inspection. This choice was made because selection for inspection has both a random and nonrandom component. The results of the study suggest that both of the government's safety programs help identify the most dangerous firms. The 2.5% of firms that do poorly in both programs have an average accident rate twice that of the mean for all other firms.     

A review of research on techniques for lifting low-lying objects: 2. Evidence for a correct technique

Teaching 'correct' lifting technique is common, with squat lifting generally recommended. However the available evidence is less clear about which technique should be favoured. The purpose of this paper was to present an accessible synthesis of the evidence to assist professionals in their decision about whether to teach a specific technique for lifting objects lying on or near the ground. Squat, stoop and semi-squat techniques are described and the psychophysical, physiological, biomechanical, psychological, performance and clinical evidence for each technique summarised. Evidence for other lifting guidelines is also presented. It is concluded that no one technique has clear evidence and that a work design approach should be the prime focus of intervention. Recommendations for correct lifting technique guidelines are given for where technique training must be provided.     

Paternalism and the young

A critical analysis is made of the concept of paternalism, and the manner in which protective measures on behalf of children often result in a denial of rights to the young. The article challenges the assumption that parents invariably know the needs of their own children, and accordingly act on their behalf. Similar reservations are made as to the capacity of official caretakers acting as agents of the state, to replace parents who are at fault. Conversely, it is suggested that children often have greater capabilities to function independently than is generally acknowledged. However, attention is also drawn to the defects in the arguments of some child-rights advocates. In sum, the article argues for the need to seek out legitimate paternalistic practices where genuinely needed, where sufficient consideration has been given to the capacities of the young for an independent life, and where sufficient sensitivity has been shown to their aspirations.     

Foreign-born professionals in the United States

This paper is an abridged version of a longer study by the same name published by the Center for Immigration Studies, 1815 H Street, NW, Washington, DC 20006.     

Assessing families and other client systems in community-based programmes: development of the CALF

Programmes providing services to children and families often face the challenge of assessing not only the child referred, but also the child’s family system and its individual members. Recognizing that household/family members can cause, contribute to or affect a child’s problems requires that human service agencies utilize assessment tools capable of assessing family members across the lifespan. The literature references many assessment tools used by clinical programmes in mental‐health settings that are not well suited to use in social service agencies with multidisciplinary staff at different skill levels. As a response to this dilemma, the authors have developed the Collaborative Assessment of Life Functioning (CALF), a user‐friendly tool that assesses various areas of life functioning. Based on Maslow’s motivation theory, person‐in‐environment and systems theories, the CALF can be used with various client systems. This paper describes the development of the tool, its purpose and use, the importance of assessment tools in the helping process and considerations for agencies wishing to use an assessment tool like the CALF. The authors also discuss the applicability of the CALF in human services and social service agency settings and with diverse client populations.     

Migration is the Driving Force of Rapid Aging in Puerto Rico: A Research Brief

Population Research and Policy Review - The combined effects of declining fertility and increased longevity have accelerated population aging in different parts of the world. Unlike other...     

Nonuniqueness of least absolute values regression

The question of nonuniqueness of the least absolute values (L₁) regression is discussed, and examples are given of situations where the L₁-regression is unique and where it has 2, 3 and 4 limiting positions. A method is proposed for finding a compromise regression line when the L₁ regression is not unique. Suggestions are made for further research.