June 2020
Beginner to intermediate
522 pages
9h 6m
Chinese
Content preview from R 语言经典实例（原书第 2 版）
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352
｜
第
11
章
11.22 创建交互关系图
11.22.1 问题
多因素方差分析：使用两个或更多分类变量作为预测变量的方差分析。需要得到预测变
量之间可能的交互关系的可视化检验。
11.22.2 解决方案
使用 interaction.plot 函数：
interaction.plot(pred1, pred2, resp)
这里，pred1 和 pred2 是两个分类预测变量，resp 是响应变量。
11.22.3 讨论
方差分析是线性回归的一种形式，因此理想情况下，每个预测变量和响应变量之间存在
线性关系。非线性的一个来源是两个预测变量之间的交互关系：当一个预测变量改变值
时，其他预测变量将改变其与响应变量的关系。检查预测变量之间的交互关系是一种基
本诊断。
faraway 包中包含一个名为 rats 的数据集。其中，treat 和 poison 是分类变量，
time 是响应变量。当绘制 poison 对 time 的图形时，我们寻找能够表明线性关系
的直线、平行线。但是，使用 interaction.plot 函数生成的图 11-8 显示存在交互
关系：
library(faraway)
data(rats)
interaction.plot(rats$poison, rats$treat, rats$time)
rats$poison
rats$treat
mean of rats$time
0.8
0.6
0.4
0.2
Ⅰ Ⅱ Ⅲ
B
D
C
A
图 11-8：
time
和
poison
的交互关系图
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