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81.
82.
Several methods exist for the problem of testing the equality of several treatments against the one-sided alternative that the treatments are better than the control. These methods include Dunnett's test, Bartholomew's likelihood-ratio test, the Abelson-Tukey-Schaafsma-Smid optimal-contrast test, and the multiple-contrast test of Mukerjee, Robertson, and Wright. A new test is proposed based on an approximation of the likelihood-ratio test of Bartholomew. This test involves using a circular cone in place of the alternative-hypothesis cone. The circular-cone test has excellent power characteristics similar to those of Bartholomew's test. Moreover, it has the advantages of being simpler to compute and may be used with unequal sample sizes.  相似文献   
83.
Although concerns have frequently been raised recently regarding the quality of life of intercollegiate athletes, information is seldom available on which college and university administrators can base policy decisions. Particularly lacking are studies that provide administrators with assessments of their own athletics programs relative to athletics programs at other institutions. We describe here a method we used in conducting a comparative evaluation of the status of student-athletes at a large public university, involving comparisons of student-athletes at this university to student-athletes at a subset of the institutions that participated in the 1987–88 National Study of Intercollegiate Athletes. By utilizing existing data sets to construct comparison samples, relative assessments of the status of student-athletes at a given institution can be performed without the excessive costs of gathering data on student-athletes at comparison institutions. Techniques employed in data collection and analysis are discussed as well as the format of the report in which the findings of the study were presented.  相似文献   
84.
Debates about regulatory efforts to monitor the delivery of health and long-term care have become commonplace in health policy. Efforts to examine the key assumptions underlying the current regulatory strategies have been limited, however. Using the board and care industry as an example, this article examines how ideology influences the regulatory strategy developed. Three ideological perspectives-a free-market approach, a market correction strategy, and a critical policy framework-are reviewed in the context of efforts to regulate board and care homes in the United States. Differences in approaches to regulating board and care are presented for each of the major perspectives.  相似文献   
85.
Examining concepts about work and love can help people increase their career success and life satisfaction. Career counselors may initiate this examination by eliciting clients' concepts about work and love. After hearing a client's ideas about work and love, counselors can compare this personal meaning to the social meaning of work and love. When this comparison reveals dysfunctional beliefs about work and love, counselors can link these beliefs to their client's career concerns. Such a linkage typically provokes a cognitive dissonance that motivates clients to modify their beliefs. Counselors can facilitate meaning modification by using client-centered and social influence techniques.  相似文献   
86.
The contemporary retreat from marriage in the United States has had a differential impact across socioeconomic and racial groups. Here, 1990 marriage rates and propensities for Virginia, North Carolina, and Wisconsin are analyzed regarding (a) the likelihood that persons in different groups ever marry and (b) patterns of partner choice with respect to race and educational level. Marriage remains strong in most race‐education groups but is substantially lower among Blacks and among those with less than 12 years of education. Patterns of partner choice have shifted to show greater symmetry between the educational levels of brides and grooms. Changes have been modest with regard to the level and pattern of interracial (Black‐White) marriage. Marriage is increasingly a union of equals, but a union chosen more by Whites than by Blacks and more by the well educated than by the poorly educated.  相似文献   
87.
This study examines school enrollment in two sub-Saharan African nations, Malawi and Kenya. The article advances a refined family economy theoretical framework for understanding variations in school enrollment. It recasts family economy frameworks to consider not only how the household institution mediates a broad social change, but also how the family institution itself may be influenced by a macroinstitutional change. The findings suggest that household structural changes, as well as changes in parents' activities and perceptions, help explain enrollment practices in rural Malawi and Kenya.  相似文献   
88.
89.
Dramatically reducing cycle times through flash development   总被引:1,自引:0,他引:1  
The reduction of cycle time has emerged as a fundamental element of new product development strategy. Many companies look solely at speed enhancement and increase the human, capital and technical resources allocated to development projects. However, additional resources do not guarantee significant reductions in cycle time. As well as speed enhancement activities, there exist two other sets of activities that are key to shortening the development cycle: those that act to prevent delays (friction) in the development process and those that define the scope of the final outcome (direction). This paper describes flash development as an alternative approach to reducing product development cycle times. Flash development works by creating a process that focuses on speed, friction and direction. The process is illustrated through an analysis of the Galileo Project at Nortel Networks.  相似文献   
90.
Recent studies demonstrating a concentration dependence of elimination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) suggest that previous estimates of exposure for occupationally exposed cohorts may have underestimated actual exposure, resulting in a potential overestimate of the carcinogenic potency of TCDD in humans based on the mortality data for these cohorts. Using a database on U.S. chemical manufacturing workers potentially exposed to TCDD compiled by the National Institute for Occupational Safety and Health (NIOSH), we evaluated the impact of using a concentration- and age-dependent elimination model (CADM) (Aylward et al., 2005) on estimates of serum lipid area under the curve (AUC) for the NIOSH cohort. These data were used previously by Steenland et al. (2001) in combination with a first-order elimination model with an 8.7-year half-life to estimate cumulative serum lipid concentration (equivalent to AUC) for these workers for use in cancer dose-response assessment. Serum lipid TCDD measurements taken in 1988 for a subset of the cohort were combined with the NIOSH job exposure matrix and work histories to estimate dose rates per unit of exposure score. We evaluated the effect of choices in regression model (regression on untransformed vs. ln-transformed data and inclusion of a nonzero regression intercept) as well as the impact of choices of elimination models and parameters on estimated AUCs for the cohort. Central estimates for dose rate parameters derived from the serum-sampled subcohort were applied with the elimination models to time-specific exposure scores for the entire cohort to generate AUC estimates for all cohort members. Use of the CADM resulted in improved model fits to the serum sampling data compared to the first-order models. Dose rates varied by a factor of 50 among different combinations of elimination model, parameter sets, and regression models. Use of a CADM results in increases of up to five-fold in AUC estimates for the more highly exposed members of the cohort compared to estimates obtained using the first-order model with 8.7-year half-life. This degree of variation in the AUC estimates for this cohort would affect substantially the cancer potency estimates derived from the mortality data from this cohort. Such variability and uncertainty in the reconstructed serum lipid AUC estimates for this cohort, depending on elimination model, parameter set, and regression model, have not been described previously and are critical components in evaluating the dose-response data from the occupationally exposed populations.  相似文献   
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