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971.
972.
A projective (2n,n,λ,1)-design is a set of n element subsets (called blocks) of a 2n-element set V having the properties that each element of V is a member of λ blocks and every two blocks have a non-empty intersection. This paper establishes existence and non-existence results for various projective (2n,n,λ,1)-designs and their subdesigns. 相似文献
973.
For the general multivariate exponential family of distributions it is shown that Rao's test criterion based on efficient scores is algebraically identical to the general chi-squared criterion based on maximum likelihood estimates and, similarly, that the Wald statistic is algebraically identical to the general minimum modified chi-squared statistic using linearization; these results are valid also for the multisample versions. Thus, these are extensions to the general exponential family of the findings due to Silvey (1970) and Bhapkar (1966), respectively, for the special case of the multinomial family.It is also shown that the general forms of the chi-squared and modified chi-squared criteria reduce to their respective well-known forms for the multivariate symmetric power series distribution. This finding is, thus, an extension of results noted by Ferguson (1958) and Clickner (1976) for the special case of the multinomial distribution. 相似文献
974.
Walter P. Blass 《Long Range Planning》1983,16(3):21-24
This paper sets out some of the traps that planners are heir to in describing archetypal planners. The author then cites the pitfalls for the planner and suggests that ideally his role is that of the guiding light of the enterprise, a signpost pointing the way at a cross-roads or correcting a wrong turning, and illuminating the way ahead. This planner is the true helpmate of the chief executive. 相似文献
975.
Religion, economic development and lethal aggression 总被引:1,自引:0,他引:1
976.
DAVID P. BARON 《Economic inquiry》1972,10(3):298-307
977.
Miller KE Barnes GM Melnick MJ Sabo DF Farrell MP 《Journal of health and social behavior》2002,43(4):436-450
Though often conflated, informal physical exercise and organized athletic participation have very different implications for adolescent sexual risk outcomes. The purpose of this research is to disaggregate strenuous exercise from sports, examine how each is associated with sexual risk, and explain the observed differences using the conceptual lens of cultural resource theory. Using a nationally representative sample of over 16,000 public and private high school students, we employ logistic regression to test hypotheses about the gender-specific and race-specific effects of strenuous exercise and athletic participation on adolescent sexual risk behavior. The results show that both forms of physical activity buffer sexual risk for girls. Strenuous exercise is associated with increased odds of sexual risk for boys. Sports and race interact to influence boys' sexual risk outcomes: Athletic participation is associated with lowered odds of sexual risk for white male adolescents, but heightened odds of sexual risk for black male adolescents. 相似文献
978.
Despite growing awareness of the complex needs of legally free children in child welfare care, relatively little empirical investigation has been done of these children and their experiences. This article reports the results of a study of length of stay and predictors of permanency in a sample of 1,366 legally free children in state custody in Washington state. A Cox proportional-hazards event history model was developed to explore the effects of gender, race, and ethnicity, and age at initial placement, on the likelihood of achieving legalized adoption or guardianship. Results indicate that older children, boys, and African American children were all significantly less likely to achieve a permanent outcome than were Caucasian children. Hispanic children, in the other hand, were significantly more likely to achieve a permanent outcome. The implications of these findings for permanency planning practice and policy development are discussed. 相似文献
979.
This article provides an overview of the history and context leading to Florida's efforts to implement an evaluation-driven research and associated quality assurance system for its juvenile justice education policies and practices. The Juvenile Justice Educational Enhancement Program began implementing Florida's evaluation research and quality assurance system to juvenile justice education in 1998. The article includes a brief summary of articles comprising this special issue of Evaluation Review that address the Juvenile Justice Educational Enhancement Program's various functions, methodological components, data, preliminary findings, continuing evaluation research efforts, and impediments. 相似文献
980.
This article discusses the role of politics in the Juvenile Justice Educational Enhancement Program's effort to use evaluation research data to inform Florida's juvenile justice education policies and practices. Through consideration of the Juvenile Justice Education Enhancement Program's experiences with privatization and the tough love and economy of scale rationales for larger and more custodial juvenile institutions, the variable role of politics is examined. Although the two examples are different, the discussion demonstrates that by maintaining an overriding commitment to its evaluation research purpose, the Juvenile Justice Educational Enhancement Program has been able to continue its data-driven policy efforts despite operating in a politically charged environment. 相似文献