如何在 R 中执行二因素方差齐性检验?
一般来说,我们可以说方差齐性检验是一种对比两个或更多变量的方差,并在它们之间存在显着差异时找出差异类型的检验。对于二因素方差齐性检验,最常用的检验之一是 Levene 检验,它可以借助 base R 中 car 包的 leveneTest 函数轻松完成。
考虑下面的数据框 −
示例
set.seed(151) x1<-sample(c("C1","C2","C3"),20,replace=TRUE) x2<-sample(c("S1","S2","S3","S4","S5"),20,replace=TRUE) y<-rnorm(20,5,2) df1<-data.frame(x1,x2,y) df1
输出
x1 x2 y 1 C2 S2 2.255857 2 C3 S5 1.726474 3 C3 S4 4.280697 4 C2 S3 7.402230 5 C2 S3 3.708252 6 C2 S4 3.978782 7 C2 S1 3.801754 8 C3 S3 6.091206 9 C2 S3 4.017412 10 C3 S3 5.383071 11 C3 S1 3.882945 12 C1 S5 6.845399 13 C1 S1 7.307996 14 C3 S4 2.255179 15 C1 S5 7.580363 16 C2 S5 7.309804 17 C2 S4 7.891359 18 C2 S3 5.522026 19 C3 S4 8.858292 20 C1 S1 3.800228
加载 car 包并在 df1 上执行 Levene 检验 −
library(car) leveneTest(y~x1*x2,data=df1) Levene's Test for Homogeneity of Variance (center = median) Df F value Pr(>F) group 9 1.5987 0.2374 10
让我们看看另一示例 −
示例
Age_group<-sample(c("First","Second"),20,replace=TRUE) Ethnicity<-sample(c("Asian","NorthAmerican","Chinese","Japanese"),20,replace=TRUE) Salary<-sample(20000:50000,20) df2<-data.frame(Age_group,Ethnicity,Salary) df2
输出
Age_group Ethnicity Salary 1 Second NorthAmerican 25678 2 Second Asian 34597 3 Second Chinese 49861 4 Second Chinese 37386 5 First Japanese 38426 6 Second NorthAmerican 45889 7 Second Asian 35033 8 Second NorthAmerican 46098 9 First Japanese 34070 10 Second Japanese 33618 11 First Japanese 35760 12 Second Chinese 33376 13 Second NorthAmerican 30630 14 First Asian 23820 15 Second Asian 40899 16 First Asian 35095 17 Second Chinese 43439 18 First Japanese 35641 19 Second Asian 41754 20 Second NorthAmerican 35337
在 df2 上执行 Levene 检验 −
leveneTest(Salary~Age_group*Ethnicity,data=df2) Levene's Test for Homogeneity of Variance (center = median) Df F value Pr(>F) group 6 0.6593 0.6835 13
广告