On a Dualization of Graphical Gaussian Models: A Correction Note

Abstract.  We correct two proofs concerning Markov properties for graphs representing marginal independence relations.     

Risk Compensation or Risk Reduction? Seatbelts,State Laws,and Traffic Fatalities*

Objective. The risk compensation hypothesis suggests that drivers enjoying greater safety will drive more recklessly and thereby impose greater risks on nonoccupants. We provide a test of the risk compensation hypothesis in the context of state seatbelt laws and belt use rates. Methods. Fixed‐effects models with policy and demographic variables are estimated using annual state data from 1985 to 2002 to test the effect of seatbelt laws and seatbelt use rates on logged fatality rates for occupants, pedestrians, motorcyclists, and all nonoccupants in separate models. Results. Contrary to the risk compensation hypothesis, the results indicate that both occupants and nonoccupants enjoy greater safety due to state mandatory use laws and increased safety belt use rates. Conclusion. Overall, seatbelt laws and the higher belt use these laws induce do not increase nonoccupant risk exposure. If anything, these laws and the accompanying increase in belt use result in safer driving behavior.     

Mandatory seat belt laws in the states. A study of fatal and severe occupant injuries

This study examines the impact of mandatory seat belt laws on fatal and incapacitating injury rates in the states. Annual data for all 50 states for the period 1975-1991 are used. Pooled time series analysis is employed. The general conclusion that emerges from this analysis is that seat belt laws significantly impact state fatal injury rates. Primary enforcement and all-seat coverage provisions appear to be particularly effective in reducing fatality rates.     

Data relaying with constraints in hierarchical sensor networks

In this paper we present and discuss several optimisation problems that arise in the management of data flow in wireless sensor networks (WSNets). We consider a hierarchical architecture for WSNets composed of sensors, relays, and relay gateways. Sensors send data they generate at a known average bit rate to relays in one hop. The relay nodes use a multi-hop mechanism to reach a set of assigned gateways which then forward the data directly to the base station. We are concerned with finding an assignment of relay gateways to relays so that certain constraints are satisfied. We define a unified model in which constraints such as lifetime, data delay, and data flow splitting are formulated in terms of four optimisation problem in graphs.     

Gender,gambling settings and gambling behaviours among undergraduate poker players

A gender divide in gambling is commonly observed among college populations. This study examines whether settings where students gamble on poker mediate the relationship between gender and poker gambling behaviours. Undergraduate poker players, 126 females and 242 males, were randomly sampled from three universities in Montreal, Canada. Three outcomes measuring risky behaviours were considered: severity of gambling problems as measured by the Problem Gambling Severity Index (PGSI), past-year poker spending and past-year poker debt. Multiple mediation analyses were conducted. The effect of gender on outcomes was analysed through three putative mediators: gambling on poker in private residences, in public locations or on the Internet. Male gender positively relates to risky gambling behaviours and occurrence of gambling in various settings. Risky gambling behaviours are positively related to gambling in various settings. Overall, the occurrence of playing poker in public locations and on the Internet emerged as significant mediators in relation to PGSI score, past-year poker spending and past-year poker debt. Given the nature of the processes by which gender is related to risky gambling behaviours among undergraduate students, gambling needs to be understood through a perspective that focuses as much on contexts as it does on individuals.     

Job Search: A Multidisciplinary Review and Research Agenda

Scholarly interest in job search has grown significantly over the years and can be located in diverse research streams: namely, economics, sociology and industrial/organizational psychology. This paper reviews these bodies of literature and makes a case for integration by proposing a multidisciplinary approach to understanding job‐seeking behaviors. To this end, the paper categorizes the respective literatures on the basis of common themes located in a conceptual multidisciplinary model of job search behaviors and outcomes. This model provides a more focused understanding of the job search literature and how it has developed in the related disciplines. Based on the review and conceptual model presented, the paper draws attention to several key areas for future research to advance the field further.     

Introductory Statistics Textbooks and the GAISE Recommendations

The six recommendations made by the Guidelines for Assessment and Instruction in Statistics Education (GAISE) committee were first communicated in 2005 and more formally in 2010. In this article, 25 introductory statistics textbooks are examined to assess how well these textbooks have incorporated the three GAISE recommendations most relevant to implementation in textbooks (statistical literacy and thinking; use of real data; stress concepts over procedures). The implementation of another recommendation (using technology) is described but not assessed. In general, most textbooks appear to be adopting the GAISE recommendations reasonably well in both exposition and exercises. The textbooks are particularly adept at using real data, using real data well, and promoting statistical literacy. Textbooks are less adept—but still rated reasonably well, in general—at explaining concepts over procedures and promoting statistical thinking. In contrast, few textbooks have easy-usable glossaries of statistical terms to assist with understanding of statistical language and literacy development. Supplementary materials for this article are available online.