排序方式: 共有23条查询结果,搜索用时 15 毫秒
21.
22.
This study examined the effect of parental divorce on the time it took adolescents to initiate their first romantic relationships. Individual differences in temperament and pubertal development and the age of the adolescent at the time of divorce were also taken into account. Hypotheses were tested using event history analysis with a sample of 1,487 Dutch adolescents. Results indicated that divorce sped up the transition to first relationship only when experienced in early adolescence. Findings are discussed in light of research on the heightened sensitivity to stress during transition periods such as the entry into adolescence. 相似文献
23.
Anastasia Ivanova Nancy Flournoy Yeonseung Chung 《Journal of statistical planning and inference》2007
We introduce a new design for dose-finding in the context of toxicity studies for which it is assumed that toxicity increases with dose. The goal is to identify the maximum tolerated dose, which is taken to be the dose associated with a prespecified “target” toxicity rate. The decision to decrease, increase or repeat a dose for the next subject depends on how far an estimated toxicity rate at the current dose is from the target. The size of the window within which the current dose will be repeated is obtained based on the theory of Markov chains as applied to group up-and-down designs. But whereas the treatment allocation rule in Markovian group up-and-down designs is only based on information from the current cohort of subjects, the treatment allocation rule for the proposed design is based on the cumulative information at the current dose. We then consider an extension of this new design for clinical trials in which the subject's outcome is not known immediately. The new design is compared to the continual reassessment method. 相似文献