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arXiv 1406.1845stat.MLstat.AP
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随机森林中可加结构的形式假设检验

Formal Hypothesis Tests for Additive Structure in Random Forests

Lucas Mentch, Giles Hooker

摘要:

虽然统计学习方法已被证明是预测建模的强大工具,但它们产生的模型的黑盒性质可能严重限制其可解释性和进行正式推理的能力。然而,当用适当的子样本构建基础学习器时,像袋装树和随机森林这样的集成学习器的自然结构已被证明具有理想的渐进特性。在这项工作中,我们证明,通过定义一个适当的网格结构的协变量空间,我们可以进行正式的假设检验变量的重要性和潜在的加性模型结构。据我们所知,这些测试代表了在随机森林等背景下研究潜在回归结构的第一个统计工具。我们开发的概念,总和部分加性,并进一步证明,可以进行测试,在没有额外的计算成本,通过估计方差内的过程中构建合奏。此外,我们提出了一种新的扩展这些测试程序,利用随机投影,以允许计算效率高的测试程序,即使当网格大小比训练集大得多,保持高功率。

英文摘要:

While statistical learning methods have proved powerful tools for predictive modeling, the black-box nature of the models they produce can severely limit their interpretability and the ability to conduct formal inference. However, the natural structure of ensemble learners like bagged trees and random forests has been shown to admit desirable asymptotic properties when base learners are built with proper subsamples. In this work, we demonstrate that by defining an appropriate grid structure on the covariate space, we may carry out formal hypothesis tests for both variable importance and underlying additive model structure. To our knowledge, these tests represent the first statistical tools for investigating the underlying regression structure in a context such as random forests. We develop notions of total and partial additivity and further demonstrate that testing can be carried out at no additional computational cost by estimating the variance within the process of constructing the ensemble. Furthermore, we propose a novel extension of these testing procedures utilizing random projections in order to allow for computationally efficient testing procedures that retain high power even when the grid size is much larger than that of the training set.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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