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# BAB 7 UJI KESAMAAN VARIANS POPULASI
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# TUGAS STATISTIK SOSIAL                                                     #
# Nama: Revanata Febry Kamia                                                 #
# NIM: 2502056017                                                            #
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# Penyelesaian dalam R untuk Uji Kesamaan Varians Populasi dengan Uji Levene

qf(.95, df1=2, df2=15)
## [1] 3.68232
varians=read.csv("C:/STATSOS/varians.csv", sep = ";")
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$Nilai, varians$Kelas)
## Warning in leveneTest.default(varians$Nilai, varians$Kelas): varians$Kelas
## coerced to factor.
## Levene's Test for Homogeneity of Variance (center = median)
##       Df F value Pr(>F)
## group  2  0.4267 0.6604
##       15
library(Rcmdr)
## Loading required package: splines
## Loading required package: RcmdrMisc
## Loading required package: sandwich
## Loading required package: effects
## Registered S3 method overwritten by 'lme4':
##   method           from
##   na.action.merMod car
## lattice theme set by effectsTheme()
## See ?effectsTheme for details.
## The Commander GUI is launched only in interactive sessions
## 
## Attaching package: 'Rcmdr'
## The following object is masked from 'package:base':
## 
##     errorCondition
leveneTest(varians$Nilai, varians$Kelas)
## Warning in leveneTest.default(varians$Nilai, varians$Kelas): varians$Kelas
## coerced to factor.
## Levene's Test for Homogeneity of Variance (center = median)
##       Df F value Pr(>F)
## group  2  0.4267 0.6604
##       15
library(lawstat)
## 
## Attaching package: 'lawstat'
## The following object is masked from 'package:car':
## 
##     levene.test
data(varians)
## Warning in data(varians): data set 'varians' not found
levene.test(varians[,"Nilai"], varians[,"Kelas"], location="median",correction.method ="zero.correction") #Sesuaikan dengan  Minitab
## 
##  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
levene.test(varians[,"Nilai"], varians[,"Kelas"], location="mean",correction.method ="zero.correction") #Sesuaikan dengan  Minitab
## 
##  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
#Uji Kesamaan Varians Populasi dengan Uji Levene (Contoh penyelesaian dengan R)

simpan=read.csv("C:/STATSOS/varians2.csv",header=TRUE, sep = ";") #Memebaca data
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)  ) } )
##   Nilai.ratarata Nilai.varians Nilai.jumlah
## 1             50      538.4615          700
qf(0.95, df1=1, df2=12)
## [1] 4.747225