tugas-bab-7-syira.R

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

##    Nilai Kelas
## 1     70     1
## 2     80     1
## 3     87     1
## 4     77     1
## 5     80     1
## 6     80     2
## 7     85     2
## 8     70     2
## 9     77     2
## 10    85     2
## 11    60     2
## 12    80     2
## 13    70     3
## 14    87     3
## 15    90     3
## 16    77     3
## 17    76     3
## 18    87     3

library(car)

## Loading required package: carData

leveneTest(varians$Nilai, as.factor(varians$Kelas), center = mean)

## Levene's Test for Homogeneity of Variance (center = mean)
##       Df F value Pr(>F)
## group  2   0.649 0.5366
##       15

library(lawstat)

## 
## Attaching package: 'lawstat'

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

levene.test(varians$Nilai, varians$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

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

## 
##  Modified robust Brown-Forsythe Levene-type test based on the absolute
##  deviations from the median with modified structural zero removal method
##  and correction factor
## 
## data:  varians$Nilai
## Test Statistic = 0.4372, p-value = 0.6557

simpan = 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))
)
simpan

##    Nilai Kelas
## 1     30     1
## 2     40     1
## 3     50     1
## 4     60     1
## 5     70     1
## 6     80     1
## 7     90     1
## 8     10     2
## 9     20     2
## 10    30     2
## 11    40     2
## 12    50     2
## 13    60     2
## 14    70     2

library(doBy)
summaryBy(Nilai ~ Kelas, data = simpan, FUN = function(x)
{c(ratarata = mean(x), varians = var(x), jumlah = sum(x))})

##   Kelas Nilai.ratarata Nilai.varians Nilai.jumlah
## 1     1             60      466.6667          420
## 2     2             40      466.6667          280

levene.test(simpan$Nilai, simpan$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:  simpan$Nilai
## Test Statistic = 1.4336e-32, p-value = 1