# TUGAS PENDALAMAN MATERI - ECOTRACK


# 1. MEMASUKKAN DATA
data <- c(22, 25, 19, 30, 24, 21, 45, 23, 20, 26, 24, 22, 18, 27, 23)

# Melihat data
data
##  [1] 22 25 19 30 24 21 45 23 20 26 24 22 18 27 23
# Mean
mean(data)
## [1] 24.6
# Median
median(data)
## [1] 23
# Modus
modus <- function(x) {
  frekuensi <- table(x)
  modus <- names(frekuensi[frekuensi == max(frekuensi)])
  as.numeric(modus)
}

modus(data)
## [1] 22 23 24
# 3. Q1, Q3, DAN IQR


# Kuartil
quantile(data, probs = c(0.25, 0.75))
##  25%  75% 
## 21.5 25.5
# Q1
Q1 <- quantile(data, 0.25)

# Q3
Q3 <- quantile(data, 0.75)

# IQR
IQR(data)
## [1] 4
Q1
##  25% 
## 21.5
Q3
##  75% 
## 25.5
IQR(data)
## [1] 4
# 4. VARIANS DAN STANDAR DEVIASI


# Varians sampel
var(data)
## [1] 41.54286
# Standar deviasi sampel
sd(data)
## [1] 6.445375
# Varians populasi (tambahan)
var_populasi <- sum((data - mean(data))^2) / length(data)
var_populasi
## [1] 38.77333
# Standar deviasi populasi
sd_populasi <- sqrt(var_populasi)
sd_populasi
## [1] 6.226824
# 5. SKEWNESS PEARSON


# Koefisien skewness Pearson
skewness_pearson <- 3 * (mean(data) - median(data)) / sd(data)

skewness_pearson
## [1] 0.7447201
# 6. VERIFIKASI SKEWNESS DENGAN R



library(e1071)

# Skewness
skewness(data)
## [1] 1.995046
# 7. RINGKASAN SEMUA HASIL

cat("Mean       :", mean(data), "\n")
## Mean       : 24.6
cat("Median     :", median(data), "\n")
## Median     : 23
cat("Modus      :", modus(data), "\n")
## Modus      : 22 23 24
cat("Q1         :", Q1, "\n")
## Q1         : 21.5
cat("Q3         :", Q3, "\n")
## Q3         : 25.5
cat("IQR        :", IQR(data), "\n")
## IQR        : 4
cat("Varians    :", var(data), "\n")
## Varians    : 41.54286
cat("SD         :", sd(data), "\n")
## SD         : 6.445375
cat("Skewness Pearson :", skewness_pearson, "\n")
## Skewness Pearson : 0.7447201
cat("Skewness e1071   :", skewness(data), "\n")
## Skewness e1071   : 1.995046