BAB 7_FAUZI HANAFI

BAB 7 - Uji Kesamaan Varians Populasi (Uji Levene)

Kasus 1: nilai ujian matematika kelas 1, 2, 3 SMA

varians = data.frame(
  Nilai = c(70, 80, 87, 77, 80,
            80, 85, 70, 77, 85, 60, 80,
            70, 87, 90, 77, 76, 87),
  Kelas = c(rep(1, 5), rep(2, 7), rep(3, 6))
)
varians

library(car)

## Loading required package: carData

leveneTest(varians$Nilai, factor(varians$Kelas))

library(lawstat)

## 
## Attaching package: 'lawstat'

## The following object is masked from 'package:car':
## 
##     levene.test

levene.test(varians$Nilai, factor(varians$Kelas), location = "mean",
            correction.method = "zero.correction")

## 
##  Classical Levene's test based on the absolute deviations from the mean
##  ( zero.correction not applied because the location is not set to median
##  )
## 
## data:  varians$Nilai
## Test Statistic = 0.64903, p-value = 0.5366

Nilai kritis F (df 2 dan 15, alpha 5%)

qf(0.95, 2, 15)

## [1] 3.68232

Kasus 2: kelas 1 dan kelas 2 SMA

varians2 = data.frame(
  Nilai = c(30, 40, 50, 60, 70, 80, 90,
            10, 20, 30, 40, 50, 60, 70),
  Kelas = c(rep(1, 7), rep(2, 7))
)
var(varians2$Nilai[varians2$Kelas == 1])

## [1] 466.6667

var(varians2$Nilai[varians2$Kelas == 2])

## [1] 466.6667

levene.test(varians2$Nilai, factor(varians2$Kelas), location = "mean",
            correction.method = "zero.correction")

## 
##  Classical Levene's test based on the absolute deviations from the mean
##  ( zero.correction not applied because the location is not set to median
##  )
## 
## data:  varians2$Nilai
## Test Statistic = 1.4336e-32, p-value = 1

qf(0.95, 1, 12)

## [1] 4.747225