Two permutation tests of equality of variances

The F-ratio test for equality of dispersion in two samples is by no means robust, while non-parametric tests either assume a common median, or are not very powerful. Two new permutation tests are presented, which do not suffer from either of these problems. Algorithms for Monte Carlo calculation of P values and confidence intervals are given, and the performance of the tests are studied and compared using Monte Carlo simulations for a range of distributional types. The methods used to speed up Monte Carlo calculations, e.g. stratification, are of wider applicability.     

A Modified Knox Test of Space-Time Clustering

Tests of space-time clustering such as the Knox test are used by epidemiologists in the preliminary analysis of datasets where an infectious aetiology is suspected. The Knox test statistic is the number of cases close in both space and time to another case. The test statistic proposed here is the excess number of such cases over that expected under H₀ of no infection. It is argued that this modified test is more powerful than the Knox test, because the test statistic is not heavily tied as is the Knox test statistic. The use of the test is illustrated with examples.     

A Behavioral Conceptualization of Aphasia

Aphasia is an acquired language impairment that affects over 1 million individuals, the majority of whom are over age 65 (Groher, 1989). This disorder has typically been conceptualized within a cognitive neuroscience framework, but a behavioral interpretation of aphasia is also possible. Skinner''s (1957) analysis of verbal behavior proposes a framework of verbal operants that can be integrated with the work of Sidman (1971) and Haughton (1980) to describe the language difficulties individuals with aphasia experience. Using this synthesis of models, we propose a new taxonomy of aphasia based on the observed deficit relations. Assessment and treatment implications are also discussed.     

Sleep Behaviors in Older African American Females Reporting Nonmalignant Chronic Pain: Understanding the Psychosocial Implications of General Sleep Disturbance

This study examined factors that influence sleep quality in older African American women (N = 181) reporting chronic pain. Participants completed a series of questions assessing demographic and behavioral characteristics, health status, pain intensity, and sleep disturbance. Findings indicated that younger participants and those experiencing poorer physical functioning reported more difficulty sleeping due to pain. Similarly, participants who reported being awakened from sleep due to pain were younger and experienced greater pain intensity. Understanding the relationship between sleep and pain in this group of women may be useful in promoting effective disease management and sleep awareness among patients, caregivers, and healthcare professionals.     

Explaining the Surge in Citizenship Applications in the 1990s: Lawful Permanent Residents in Texas

Objective . We explore the increase in citizenship applications in the mid–1990s in order to test popular explanations for them, such as the consequences of IRCA legalization, fear of loss of public benefits, and effects of citizenship outreach programs. Methods . We rely on a nonrandom sample of 526 lawful permanent residents in four Texas cities. About half had applied for citizenship and all were taking affirmative steps via participation in citizenship or English–language classes. Results . Having received amnesty under IRCA predicts rapid application for citizenship upon eligibility but is not associated with greater mastery of the naturalization process or better English skills. Fear of losing eligibility for public benefits and campaigns promoting naturalization motivated about one–quarter of citizenship applicants. Much larger proportions cite their desire to participate fully in American life, to sponsor the immigration of relatives, and to ensure opportunities for their children. The main obstacle they identify is limited English proficiency. Conclusions . Although factors peculiar to the political environment of the 1990s affected many permanent residents, most cited traditional incentives having to do with investment in opportunities for themselves and their families. Our data suggest that the most effective way to facilitate naturalization is to devote more resources to English–language training.     

Particular polyglots: multilingual students with autism

Many American children with autism live in multilingual environments. Yet an almost diametric contrast exists between the advice of practitioners and the recommendations found in scholarly literature. Whereas practitioners almost unanimously counsel that children on the autism spectrum be exposed to English alone, an increasing number of scholars have argued the potential benefits for these children of learning their parents’ native language as well. This paper argues that, in fact, language recommendations for children on the spectrum should fall somewhere between these two poles and be tailored to individual children and their families.     

Family Well-Being Concerns of Grandparents in Skipped Generation Families

This study examined the family well-being concerns of grandparents in skipped-generation families. Co-resident grandparents who are responsible for raising their grandchildren completed surveys, focus groups, or individual interviews. Service providers to skipped-generation families also participated in individual interviews to provide an additional perspective to grandparents' concerns. Results indicated 5 levels of concerns: intrapersonal, interpersonal, organizational or institutional, policy, and societal. Concerns at different levels were interrelated and pointed to the need for multilevel interventions to help these families. Implications of the findings for future interventions with skipped-generation families are discussed.