时 间：2023年6月16日（周五）10：00-11：00
地 点: 腾讯线上会议：272566659
题 目：Multifold Cross-Validation Model Averaging for Generalized Additive Partial Linear Models
报告人：许王莉 中国人民大学教授
主持人：项冬冬 教授
主 办：统计学院
摘 要：
Generalized Additive Partial Linear Models (GAPLMs) are appealing for model interpretation and prediction. However, for GAPLMs, the covariates and the degree of smoothing in the nonparametric parts are often difficult to determine in practice. To address this model selection uncertainty issue, we develop a computationally feasible Model Averaging (MA) procedure. The model weights are data-driven and selected based on multifold Cross-Validation (CV) (instead of leave-one-out) for computational saving. When all the candidate models are misspecified, we show that the proposed MA estimator for GAPLMs is asymptotically optimal in the sense of achieving the lowest possible Kullback-Leibler loss. In the other scenario where the candidate model set contains at least one quasi-correct model, the weights chosen by the multifold CV are asymptotically concentrated on the quasi-correct models. As a by-product, we propose a variable importance measure to quantify the importances of the predictors in GAPLMs based on the MA weights. It is shown to be able to asymptotically identify the variables in the true model. Moreover, when the number of candidate models is very large, a model screening method is provided. Numerical experiments show the superiority of the proposed MA method over some existing model averaging and selection methods.
报告人简介：
许王莉，中国人民大学统计学教授，博士生导师。近年来一直从事模型拟合优度检验，高维数据分析，随机缺失数据，两阶段抽样数据以及纵向数据分析等方面的统计推断研究。先后主持了4项国家自然科学基金，以及教育部人文社会科学重点研究基地重大项目，北京市自然科学基金重点项目和教育部人文社科基金等多项科研课题, 在统计学国际一流期刊发表论文百余篇，并在科学出版社合作出版《非参数蒙特卡洛检验及其应用》和单著《缺失数据的模型检验及其应用》。