Comparison of Robust Estimators of Standard Deviation in Normal Distributions Within the Context of Quality Control

Pitman criterion is used in simulation to determine the “closer” estimator of the standard deviation among selected choices. The initial simulation utilizes a standard normal distribution from which samples are taken of specific sizes. Popular and commonly used estimators of standard deviation are compared with the known population standard deviation in this study. Closeness criterion is calculated for each comparison and sample size. A secondary simulation applies the findings to variables control charts, in order to verify the ability of each estimator to identify out-of-control conditions.     

Efficacy of a Web-Based,Tailored, Alcohol Prevention/Intervention Program for College Students: Initial Findings

Abstract

Objective: Reduce college student at-risk drinking (ARD) using a Web-based brief motivational alcohol prevention/intervention called Michigan Prevention and Alcohol Safety for Students (M-PASS). Participants: Participants included 1,137 randomly sampled first-year college students, including 59% female, 80% white, and averaged age 18.1 years. Methods: Intervention group participants (n = 616) attended 4 online M-PASS sessions, receiving feedback tailored to individual drinking patterns and concepts from 4 behavior change theories. Control group participants (n = 521) completed a mid-phase survey, and both groups were surveyed at baseline and posttest. Results: Evidence of M-PASS's efficacy was found. The intervention was associated with advanced stage of change, lower tolerance of drinking and drink/driving, fewer reasons to drink, and use of more strategies to avoid ARD. Preliminary evidence of behavioral change was also found. Efficacy was greater for women than men. Conclusions: Web-based programs may be useful in reducing alcohol-related risk among college students. Further evaluation is needed.     

Access to Health Care: Social Determinants of Preventive Cancer Screening Use in Northern British Columbia

The purpose of this study was to examine theextent to which social factors are influentialin determining women's access to cancerscreening services in Prince George, BritishColumbia. Specifically, this study evaluatedthe association of age, income, education, workstatus, disability, marital status, andimmigrant status with previous use of screeningmammography and Pap tests. Data was obtainedfrom the 1994 National Population HealthSurvey, which contains a sample of 416 womenfrom the Prince George area. A series oflogistic regression analyses were used todistinguish ever versus never beenscreened as well as recency of previousscreening. Participation rates in screeningmammography in Prince George are comparativelyhigh; however, no association was found betweensocial factors and previous mammography use.This suggests women in Prince George areparticipating in mammography servicesregardless of social background. Participationrates in Pap test screening in Prince Georgeare high and are similar to provincialaverages; however, while a large percentage ofwomen have been screened, this percentagevaries across social groups. Immigrant women,single women, and women with less education areover represented among women who have never hada Pap test. In addition, older women are lesslikely to obtain a recent Pap test whencompared to younger women. This study suggeststhat certain groups of women in northernBritish Columbia experience low participationin health services, resulting in a higher riskfor poor health and a poor quality of life.     

Time together,time apart: An analysis of wives' solitary time and shared time with spouses

The time spouses spend together in household work activities, leisure activities, and in eating are analyzed and compared with the time spent alone by wives in these same activities. The purpose of the analysis is to distinguish between two hypotheses: (a) that the time spent by spouses together in the same activity is charged with extra meaning when compared with the time spent by the wife alone in the same activity; and (b) that the time spent by spouses together in the same activity is a perfect substitute for time spent alone in the same activity by the wife. Multivariate probit, OLS and Tobit analyses are conducted with data taken from the 1977–78 NE-113 Time-Use Data for Louisiana, New York, Utah, and Wisconsin. Statistical tests confirm the hypothesis that shared times in the three activities studied are charged with extra meaning when compared with wives' solitary time in the same activities. Solitary times spent by the wife in the three activities are negatively related with family income. Solitary time spent by wives in household work activities and in leisure activities are positively related to husband's price of time. Spouses' shared times in these activities rise and wives' solitary times fall on weekends.Thanks are due to Bob Avery, Barbara Brown, Robin Douthitt, Jenny Gerner, Jutta Joesch, Sally Lloyd, Cathy Zick, Peter Zorn, members of S-206 Time-Use Regional Committee, the graduate research workshop of the Department of Family and Consumer Studies, University of Utah, the seminar participants at Utah State University, and the seminar participants of the Department of Family Economics and Management, University of Missouri for stimulating, cautionary, and corrective discussions pertaining to this paper. Any remaining errors and obscurities are the responsibility of the authors.W. Keith Bryant is Professor, Consumer Economics and Housing, 117D Martha Van Rensselaer Hall, Cornell University, Ithaca, NY 14853. Dr. Bryant received his Ph.D. from Michigan State University. Yan Wang is MacNamara Post-Doctorate Fellow, The World Bank, Washington, DC. She received her Ph.D. from Cornell University.     

Hypermaps: a representation of perceptions in conflicts

An approach to the modelling of conflicts, which is based upon personal construct psychology, is described. Use is made of the idea of cognitive mapping as a way of representing individual perceptions of a situation, and the relationships between the maps held by individuals who are in conflict are expressed by introducing the concept of ‘hypermaps’. The resulting implications for applications of the hypergame approach in practical studies are discussed     

Computing a population budget from sequentially sacrificed, replicated cultures

Summary When a population budget must be obtained from censuses based on replicated, sacrificed cultures, it is difficult to obtain estimates of transition probabilities and of the errors of such estimates, because there is no logical basis for pairing successive census counts. In a study of this nature estimating a population budget of immature stages of the housefly, the problem was solved by a randomization treatment of the original census results obtained at two densities. One hundred randomly generated census matrices over all census times for each density were smoothed to remove the effects of sampling error and a population budget constructed according to defined rules. Transition probabilities computed from the population budget were plotted on triangular coordinate paper and mean probabilities, 95% confidence regions for these means, and 95% equal frequency ellipses computed. All computations and the graphing of the results were carried out on a digital computer. The computer program, available from the authors, is written in FORTRAN IV and could be easily modified for similar studies. Contribution No. 1364 from the Department of Entomology, The University of Kansas. This study has been supported by the Medical Research and Development Command of the Office of the Surgeon General of the Army under contract No. DA-49-007-MD-738, U.S.A. and by a Public Health research career program award (No. 3-K3-GM-22, 021-01S1) from the National Institute of General Medical Sciences, U.S.A. to RobertR. Sokal. It was carried out during the tenure of a National Science Foundation predoctoral fellowship by EdwinH. Bryant. The authors appreciate the help of Dr.F.J. Rohlf with computational aspects.     

Abortion: a psychiatric patient's right to choose

1. Competent mentally ill patients should be allowed to terminate pregnancy. 2. It is the responsibility of the staff to provide the patient with a safe, supportive, and respectful environment. 3. Early and frequent staff processing opportunities should be offered to clarify any underlying issues.