Sample size determination in fixed‐dose combination drug studies

In this paper, the application of the intersection–union test method in fixed‐dose combination drug studies is discussed. An approximate sample size formula for the problem of testing the efficacy of a combination drug using intersection–union tests is proposed. The sample sizes obtained from the formula are found to be reasonably accurate in terms of attaining the target power 1?β for a specified β. Copyright © 2003 John Wiley & Sons, Ltd.     

Double Jeopardy: Work Ethic Differences in Youth at Risk of School Failure

The purpose of this study was to determine if work ethic differed for a sample of 152 selected 9th-grade students categorized by risk of school failure and by gender. Work ethic attributes were measured using the Occupational Work Ethic Inventory (Petty, 1993). Results of a two-way multivariate analysis of variance indicated significant work ethic differences in main effects of at-risk classification and gender for dependent variables of interpersonal skills, initiative, and being dependable. Interaction effects were not significant. Underlying constructs indicated that adolescents with greater degrees of risk were less dependable and that girls in the study were more dependable than boys.     

Flood Protection Diversification to Reduce Probabilities of Extreme Losses

Recent catastrophic losses because of floods require developing resilient approaches to flood risk protection. This article assesses how diversification of a system of coastal protections might decrease the probabilities of extreme flood losses. The study compares the performance of portfolios each consisting of four types of flood protection assets in a large region of dike rings. A parametric analysis suggests conditions in which diversifications of the types of included flood protection assets decrease extreme flood losses. Increased return periods of extreme losses are associated with portfolios where the asset types have low correlations of economic risk. The effort highlights the importance of understanding correlations across asset types in planning for large‐scale flood protection. It allows explicit integration of climate change scenarios in developing flood mitigation strategy.     

Older People's Family Contacts and Long-term Care Expenditure in OECD Countries: A Comparative Approach Using Qualitative Comparative Analysis

In recent decades there has been a suggestion that public and private long-term care (LTC) expenditure might be replacing traditional family care for older people. The decline of family contact is known to be more advanced in some OECD countries than others, with southern Europe identified as where family contact is still strong. This article explores at a country level whether there is an association between levels of expenditure on long-term care and the availability of family contacts. Qualitative Comparative Analysis is used as a comparative method, so as to use national quantitative indicators with a small sample of countries. An association between higher levels of family contact and lower levels of expenditure on LTC is suggested, but it is weakened by a number of untypical cases. Countries that defy this relationship have government care policies that seek to promote informal social care through the family contact that continues to be available. Austria, Canada, Great Britain and Japan are discussed in this context.     

An efficient experiment to study superconducting ceramics

Materials formulation and processing research are important industrial processes and most materials know-how comes from physical experiments. Our impression, based on discussions with materials scientists, is that statistically planned experiments are infrequently used in materials research. This scientific and engineering area provides an excellent opportunity for both using the available techniques of statistically planned experiments, including mixture experiments, and identifying opportunities for collaborative research leading to further advances in statistical methods for scientists and engineers. This paper describes an application of SchefK's (1958) simplex approach for mixture experiments to formulation of high-temperature superconducting compounds. This example has given us better appreciation of the needs of materials scientists and has provided us opportunities for further collaborative research.     

On selecting populations better than a control: weibull populations case

Consider k( k ≥ 1) independent Weibull populations and a control population which is also Weibull. The problem of identifying which of these k populations are better than the control using shape parameter as a criterion is considered. We allow the possibility of making at most m(0 ≤ m < k) incorrect identifications of better populations. This allowance results in significant savings in sample size. Procedures based on simple linear unbiased estimators of the reciprocal of the shape parameters of these populations are proposed. These procedures can be used for both complete and Type II-censored samples. A related problem of confidence intervals for the ratio of ordered shape parameters is also considered. Monte Carlo simulations as well as both chi-square and normal approximations to the solutions are obtained.     

Rates of Asymptomatic Nonurethral Gonorrhea and Chlamydia in a Population of University Men Who Have Sex With Men

ABSTRACT

Objective: To evaluate a text message (SMS) program as a booster to an in-person alcohol intervention with mandated college students. Participants: Undergraduates (N = 224; 46% female) who violated an on-campus alcohol policy over a 2-semester period in 2014. Methods: The SMS program sent drinking-related queries each Thursday and Sunday and provided tailored feedback for 6 weeks. Response rates to SMS drinking-related queries and the associations between weekend drinking plans, drinking-limit goal commitment, and alcohol consumption were examined. Gender differences were explored. Results: Ninety percent of SMS queries were completed. Weekend binge drinking decreased over 6 weeks, and drinking-limit goal commitment was associated with less alcohol consumption. Compared with women, men had greater reductions in alcohol consumption when they committed to a drinking-limit goal. Conclusions: Preliminary evidence suggests that an SMS program could be useful as a booster for helping mandated students reduce weekend binge drinking.