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用在设计阶段可以收集到的3个规模度量分析类规模对面向对象度量与易维护性之间关联关系的混和效果.为得到尽可能通用的结论,在127个C＋＋系统和113个Java系统上分析类规模的混和效果.首先,对每个面向对象度量,在单个系统上计算代表由类规模造成的关联扭曲的间接效果和它的方差.然后,利用统计的元分析方法计算这些系统上的平均间接效果并判断它是否显著地区别于零.实验结果表明,不论使用哪个类规模度量进行分析,类规模对面向对象度量与易维护性之间关联关系的混和效果通常是存在的.因此,验证面向对象度量与易维护性之间关系的实验研究应将类规模视为一个混和变量. 相似文献
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Paul H. Lee 《Research quarterly for exercise and sport》2017,88(2):203-208
Purpose: Some confounders are nonlinearly associated with dependent variables, but they are often adjusted using a linear term. The purpose of this study was to examine the error of mis-specifying the nonlinear confounding effect. Methods: We carried out a simulation study to investigate the effect of adjusting for a nonlinear confounder in the estimation of a causal relationship between the exposure and outcome in 3 ways: using a linear term, binning into 5 equal-size categories, or using a restricted cubic spline of the confounder. Continuous, binary, and survival outcomes were simulated. We examined the confounder across varying measurement error. In addition, we performed a real data analysis examining the 3 strategies to handle the nonlinear effects of accelerometer-measured physical activity in the National Health and Nutrition Examination Survey 2003–2006 data. Results: The mis-specification of a nonlinear confounder had little impact on causal effect estimation for continuous outcomes. For binary and survival outcomes, this mis-specification introduced bias, which could be eliminated using spline adjustment only when there is small measurement error of the confounder. Real data analysis showed that the associations between high blood pressure, high cholesterol, and diabetes and mortality adjusted for physical activity with restricted cubic spline were about 3% to 11% larger than their counterparts adjusted with a linear term. Conclusion: For continuous outcomes, confounders with nonlinear effects can be adjusting with a linear term. Spline adjustment should be used for binary and survival outcomes on confounders with small measurement error. 相似文献
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对因析设计在混杂度量方面的前沿研究进行了回顾,包括二水平正规设计的最大分辨度准则和最小低阶混杂准则,二水平非正规设计的J值,素数幂情形时的最小杂合准则,以及混合水平时的广义最小低阶混杂准则,另外也包括一般最小低阶混杂准则和基于矩阵像的混杂度量准则。 相似文献
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通过矩阵象(MI)技术,给出正交表的混杂度概念,并证明了混杂定理,对于饱和正交表,所有混杂度之和等于交互作用的自由度,最后给出混合水平情形下的交互作用分布例子。 相似文献
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《信阳师范学院学报(哲学社会科学版)》2018,(3):102-105
《老残游记》是一部具有很大混杂性的小说,既有对晚清时期帝国世态风物的写真,又有自我辩诬泄愤的自传式叙述,还花费许多笔墨表达了对政治时局的关切和评判,而这些都没有统一在小说的叙述中。《老残游记》既有谴责、政治、侦探、公案等晚清通俗小说元素,又有为当时士人群体所喜的抒情元素。《老残游记》混杂性的原因在于作者创作欲求的多样性、读者市场的倾向性和小说体式的实验性。 相似文献
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通过矩阵象(MI)技术,给出正交表的混杂度概念,并证明了混杂定理,对于饱和正交表,所有混杂度之和等于交互作用的自由度,最后给出混合水平情形下的交互作用分布例子。 相似文献
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