A. Persiapan

A.1 Instalasi Package R yang diperlukan

# Menentukan Lokasi Mirror, di Indonesia ada di BPPT
r <- getOption("repos")
r["CRAN"] <- "https://repo.bppt.go.id/cran/"
options(repos = r)

# Nama Package yang diperlukan
packages <- c('readxl', 'agricolae')

# Fungsi Cek Apakah Package ada? Jika tidak ada, maka Install. Jika Sudah Di install maka Load!
for (p in packages){
  if(!require(p, character.only = T)){
    install.packages(p)
  }
  library(p,character.only = T)
}
## Loading required package: readxl
## Loading required package: agricolae

A.2 Data

Silahkan unduh data yang diperlukan KLIK SINI untuk DOWNLOAD Data One Way Anova. Lalu tempatkan pada Folder yang sesuai. Kalau di Tutorial ini, diletakkan di Drive E dengan nama Folder R

B. Contoh 1 : Nilai Siswa SMA berdasarkan Tempat Duduk

B.1 Akses R ke Data

library("readxl")
contoh1 <- read_excel("E:\\R\\One Way Anova.xlsx", sheet = "contoh1")
contoh1
## # A tibble: 24 x 2
##    Grup   Nilai
##    <chr>  <dbl>
##  1 Depan     82
##  2 Depan     83
##  3 Depan     97
##  4 Depan     93
##  5 Depan     55
##  6 Depan     67
##  7 Depan     53
##  8 Tengah    83
##  9 Tengah    78
## 10 Tengah    68
## # ... with 14 more rows

B.2 One Way Anova

contoh1$Grup<-as.factor(contoh1$Grup)
anova1<-aov(Nilai~Grup, data=contoh1)
summary(anova1)
##             Df Sum Sq Mean Sq F value  Pr(>F)   
## Grup         2   1902   950.8   5.896 0.00928 **
## Residuals   21   3386   161.3                   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
boxplot(Nilai~Grup, data=contoh1, id.method="y")

B.3 Uji Lanjut

library("agricolae")
LSD.test(anova1,"Grup",p.adj="hommel",console=TRUE)
## 
## Study: anova1 ~ "Grup"
## 
## LSD t Test for Nilai 
## P value adjustment method: hommel 
## 
## Mean Square Error:  161.2532 
## 
## Grup,  means and individual ( 95 %) CI
## 
##             Nilai      std r      LCL      UCL Min Max
## Belakang 53.50000  8.96023 8 44.16333 62.83667  38  66
## Depan    75.71429 17.63249 7 65.73297 85.69560  53  97
## Tengah   67.11111 10.94811 9 58.30842 75.91381  51  83
## 
## Alpha: 0.05 ; DF Error: 21
## Critical Value of t: 2.079614 
## 
## Groups according to probability of means differences and alpha level( 0.05 )
## 
## Treatments with the same letter are not significantly different.
## 
##             Nilai groups
## Depan    75.71429      a
## Tengah   67.11111     ab
## Belakang 53.50000      b
HSD.test(anova1,"Grup",console=TRUE)
## 
## Study: anova1 ~ "Grup"
## 
## HSD Test for Nilai 
## 
## Mean Square Error:  161.2532 
## 
## Grup,  means
## 
##             Nilai      std r Min Max
## Belakang 53.50000  8.96023 8  38  66
## Depan    75.71429 17.63249 7  53  97
## Tengah   67.11111 10.94811 9  51  83
## 
## Alpha: 0.05 ; DF Error: 21 
## Critical Value of Studentized Range: 3.564625 
## 
## Groups according to probability of means differences and alpha level( 0.05 )
## 
## Treatments with the same letter are not significantly different.
## 
##             Nilai groups
## Depan    75.71429      a
## Tengah   67.11111     ab
## Belakang 53.50000      b

C. Contoh 2 : Distorsi Suara Berdasarkan Lapisan Pita Suara

C.1 Akses R ke Data

library("readxl")
contoh2 <- read_excel("E:\\R\\One Way Anova.xlsx", sheet = "contoh2")
contoh2
## # A tibble: 22 x 2
##    Lapisan Distorsi
##    <chr>      <dbl>
##  1 A             10
##  2 A             15
##  3 A              8
##  4 A             12
##  5 A             15
##  6 B             14
##  7 B             18
##  8 B             21
##  9 B             15
## 10 C             17
## # ... with 12 more rows

C.2 One Way Anova

contoh2$Lapisan<-as.factor(contoh2$Lapisan)
anova2<-aov(Distorsi~Lapisan, data=contoh2)
summary(anova2)
##             Df Sum Sq Mean Sq F value Pr(>F)  
## Lapisan      3     68  22.667    4.34 0.0181 *
## Residuals   18     94   5.222                 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
boxplot(Distorsi~Lapisan, data=contoh2, id.method="y")

C.3 Uji Lanjut

library("agricolae")
LSD.test(anova2,"Lapisan",p.adj="hommel",console=TRUE)
## 
## Study: anova2 ~ "Lapisan"
## 
## LSD t Test for Distorsi 
## P value adjustment method: hommel 
## 
## Mean Square Error:  5.222222 
## 
## Lapisan,  means and individual ( 95 %) CI
## 
##   Distorsi      std r       LCL      UCL Min Max
## A       12 3.082207 5  9.852898 14.14710   8  15
## B       17 3.162278 4 14.599467 19.40053  14  21
## C       16 1.414214 7 14.185368 17.81463  14  18
## D       15 1.673320 6 13.039973 16.96003  12  17
## 
## Alpha: 0.05 ; DF Error: 18
## Critical Value of t: 2.100922 
## 
## Groups according to probability of means differences and alpha level( 0.05 )
## 
## Treatments with the same letter are not significantly different.
## 
##   Distorsi groups
## B       17      a
## C       16      a
## D       15     ab
## A       12      b
HSD.test(anova2,"Lapisan",console=TRUE)
## 
## Study: anova2 ~ "Lapisan"
## 
## HSD Test for Distorsi 
## 
## Mean Square Error:  5.222222 
## 
## Lapisan,  means
## 
##   Distorsi      std r Min Max
## A       12 3.082207 5   8  15
## B       17 3.162278 4  14  21
## C       16 1.414214 7  14  18
## D       15 1.673320 6  12  17
## 
## Alpha: 0.05 ; DF Error: 18 
## Critical Value of Studentized Range: 3.996978 
## 
## Groups according to probability of means differences and alpha level( 0.05 )
## 
## Treatments with the same letter are not significantly different.
## 
##   Distorsi groups
## B       17      a
## C       16      a
## D       15     ab
## A       12      b