Modul 1 Praktikum PSD 2023/2024 Semester Ganjil

Kembali ke Pengantar Sains Data

Versi file .R dari modul ini bisa diunduh: Modul 1.R

Dataset “Iris” yang digunakan di modul ini bisa langsung diakses melalui R, atau bisa juga diunduh:

PART 1: Operasi Dasar

Operasi Dasar. Layaknya matematika pada umumnya, R dapat malakukan operasi dasar.

Cara me-run sebuah program adalah dengan ctrl + Enter

Untuk me-run beberapa program sekaligus, Anda select programnya, lalu ctrl + Enter

2+3
[1] 5
7-5
[1] 2
3*5
[1] 15
3/4
[1] 0.75
2:4
[1] 2 3 4
2**3
[1] 8

Pendefinisian variable pada R dapat menggunakan <- atau =

Cara pendefinisian variable adalah sebagai berikut

apel<- 4
jeruk <- 7

Kiri merupakan nama variable dan kanan merupakan nilai variable

Untuk memanggil variable, cukup Anda ketik namanya

apel
[1] 4

lalu run.

Layaknya sebuah angka, variable tersebut dapat melakukan opreasi dasar

apel+jeruk
[1] 11
apel-jeruk
[1] -3
apel*jeruk
[1] 28
apel/jeruk
[1] 0.5714286

Variable juga dapat didefinisikan oleh variable variable lainnya

banyakbuah <- jeruk+apel 
banyakbuah
[1] 11

Variable yang telah terdefinisi dapat dilihat pada enviorment (sebelah kanan script)

atau menggunakan

ls() #lihat list variabel
[1] "apel"       "banyakbuah" "jeruk"     

untuk menghapus variable, gunakan fungsi rm

rm(banyakbuah) #hapus variabel banyakbuah

untuk menghapus semua variabel gunakan

rm(list=ls())

DATA VIZ

Import data

import data iris (dataset built-in nya R)

data("iris")
iris #liat datanya di console
    Sepal.Length Sepal.Width Petal.Length Petal.Width    Species
1            5.1         3.5          1.4         0.2     setosa
2            4.9         3.0          1.4         0.2     setosa
3            4.7         3.2          1.3         0.2     setosa
4            4.6         3.1          1.5         0.2     setosa
5            5.0         3.6          1.4         0.2     setosa
6            5.4         3.9          1.7         0.4     setosa
7            4.6         3.4          1.4         0.3     setosa
8            5.0         3.4          1.5         0.2     setosa
9            4.4         2.9          1.4         0.2     setosa
10           4.9         3.1          1.5         0.1     setosa
11           5.4         3.7          1.5         0.2     setosa
12           4.8         3.4          1.6         0.2     setosa
13           4.8         3.0          1.4         0.1     setosa
14           4.3         3.0          1.1         0.1     setosa
15           5.8         4.0          1.2         0.2     setosa
16           5.7         4.4          1.5         0.4     setosa
17           5.4         3.9          1.3         0.4     setosa
18           5.1         3.5          1.4         0.3     setosa
19           5.7         3.8          1.7         0.3     setosa
20           5.1         3.8          1.5         0.3     setosa
21           5.4         3.4          1.7         0.2     setosa
22           5.1         3.7          1.5         0.4     setosa
23           4.6         3.6          1.0         0.2     setosa
24           5.1         3.3          1.7         0.5     setosa
25           4.8         3.4          1.9         0.2     setosa
26           5.0         3.0          1.6         0.2     setosa
27           5.0         3.4          1.6         0.4     setosa
28           5.2         3.5          1.5         0.2     setosa
29           5.2         3.4          1.4         0.2     setosa
30           4.7         3.2          1.6         0.2     setosa
31           4.8         3.1          1.6         0.2     setosa
32           5.4         3.4          1.5         0.4     setosa
33           5.2         4.1          1.5         0.1     setosa
34           5.5         4.2          1.4         0.2     setosa
35           4.9         3.1          1.5         0.2     setosa
36           5.0         3.2          1.2         0.2     setosa
37           5.5         3.5          1.3         0.2     setosa
38           4.9         3.6          1.4         0.1     setosa
39           4.4         3.0          1.3         0.2     setosa
40           5.1         3.4          1.5         0.2     setosa
41           5.0         3.5          1.3         0.3     setosa
42           4.5         2.3          1.3         0.3     setosa
43           4.4         3.2          1.3         0.2     setosa
44           5.0         3.5          1.6         0.6     setosa
45           5.1         3.8          1.9         0.4     setosa
46           4.8         3.0          1.4         0.3     setosa
47           5.1         3.8          1.6         0.2     setosa
48           4.6         3.2          1.4         0.2     setosa
49           5.3         3.7          1.5         0.2     setosa
50           5.0         3.3          1.4         0.2     setosa
51           7.0         3.2          4.7         1.4 versicolor
52           6.4         3.2          4.5         1.5 versicolor
53           6.9         3.1          4.9         1.5 versicolor
54           5.5         2.3          4.0         1.3 versicolor
55           6.5         2.8          4.6         1.5 versicolor
56           5.7         2.8          4.5         1.3 versicolor
57           6.3         3.3          4.7         1.6 versicolor
58           4.9         2.4          3.3         1.0 versicolor
59           6.6         2.9          4.6         1.3 versicolor
60           5.2         2.7          3.9         1.4 versicolor
61           5.0         2.0          3.5         1.0 versicolor
62           5.9         3.0          4.2         1.5 versicolor
63           6.0         2.2          4.0         1.0 versicolor
64           6.1         2.9          4.7         1.4 versicolor
65           5.6         2.9          3.6         1.3 versicolor
66           6.7         3.1          4.4         1.4 versicolor
67           5.6         3.0          4.5         1.5 versicolor
68           5.8         2.7          4.1         1.0 versicolor
69           6.2         2.2          4.5         1.5 versicolor
70           5.6         2.5          3.9         1.1 versicolor
71           5.9         3.2          4.8         1.8 versicolor
72           6.1         2.8          4.0         1.3 versicolor
73           6.3         2.5          4.9         1.5 versicolor
74           6.1         2.8          4.7         1.2 versicolor
75           6.4         2.9          4.3         1.3 versicolor
76           6.6         3.0          4.4         1.4 versicolor
77           6.8         2.8          4.8         1.4 versicolor
78           6.7         3.0          5.0         1.7 versicolor
79           6.0         2.9          4.5         1.5 versicolor
80           5.7         2.6          3.5         1.0 versicolor
81           5.5         2.4          3.8         1.1 versicolor
82           5.5         2.4          3.7         1.0 versicolor
83           5.8         2.7          3.9         1.2 versicolor
84           6.0         2.7          5.1         1.6 versicolor
85           5.4         3.0          4.5         1.5 versicolor
86           6.0         3.4          4.5         1.6 versicolor
87           6.7         3.1          4.7         1.5 versicolor
88           6.3         2.3          4.4         1.3 versicolor
89           5.6         3.0          4.1         1.3 versicolor
90           5.5         2.5          4.0         1.3 versicolor
91           5.5         2.6          4.4         1.2 versicolor
92           6.1         3.0          4.6         1.4 versicolor
93           5.8         2.6          4.0         1.2 versicolor
94           5.0         2.3          3.3         1.0 versicolor
95           5.6         2.7          4.2         1.3 versicolor
96           5.7         3.0          4.2         1.2 versicolor
97           5.7         2.9          4.2         1.3 versicolor
98           6.2         2.9          4.3         1.3 versicolor
99           5.1         2.5          3.0         1.1 versicolor
100          5.7         2.8          4.1         1.3 versicolor
101          6.3         3.3          6.0         2.5  virginica
102          5.8         2.7          5.1         1.9  virginica
103          7.1         3.0          5.9         2.1  virginica
104          6.3         2.9          5.6         1.8  virginica
105          6.5         3.0          5.8         2.2  virginica
106          7.6         3.0          6.6         2.1  virginica
107          4.9         2.5          4.5         1.7  virginica
108          7.3         2.9          6.3         1.8  virginica
109          6.7         2.5          5.8         1.8  virginica
110          7.2         3.6          6.1         2.5  virginica
111          6.5         3.2          5.1         2.0  virginica
112          6.4         2.7          5.3         1.9  virginica
113          6.8         3.0          5.5         2.1  virginica
114          5.7         2.5          5.0         2.0  virginica
115          5.8         2.8          5.1         2.4  virginica
116          6.4         3.2          5.3         2.3  virginica
117          6.5         3.0          5.5         1.8  virginica
118          7.7         3.8          6.7         2.2  virginica
119          7.7         2.6          6.9         2.3  virginica
120          6.0         2.2          5.0         1.5  virginica
121          6.9         3.2          5.7         2.3  virginica
122          5.6         2.8          4.9         2.0  virginica
123          7.7         2.8          6.7         2.0  virginica
124          6.3         2.7          4.9         1.8  virginica
125          6.7         3.3          5.7         2.1  virginica
126          7.2         3.2          6.0         1.8  virginica
127          6.2         2.8          4.8         1.8  virginica
128          6.1         3.0          4.9         1.8  virginica
129          6.4         2.8          5.6         2.1  virginica
130          7.2         3.0          5.8         1.6  virginica
131          7.4         2.8          6.1         1.9  virginica
132          7.9         3.8          6.4         2.0  virginica
133          6.4         2.8          5.6         2.2  virginica
134          6.3         2.8          5.1         1.5  virginica
135          6.1         2.6          5.6         1.4  virginica
136          7.7         3.0          6.1         2.3  virginica
137          6.3         3.4          5.6         2.4  virginica
138          6.4         3.1          5.5         1.8  virginica
139          6.0         3.0          4.8         1.8  virginica
140          6.9         3.1          5.4         2.1  virginica
141          6.7         3.1          5.6         2.4  virginica
142          6.9         3.1          5.1         2.3  virginica
143          5.8         2.7          5.1         1.9  virginica
144          6.8         3.2          5.9         2.3  virginica
145          6.7         3.3          5.7         2.5  virginica
146          6.7         3.0          5.2         2.3  virginica
147          6.3         2.5          5.0         1.9  virginica
148          6.5         3.0          5.2         2.0  virginica
149          6.2         3.4          5.4         2.3  virginica
150          5.9         3.0          5.1         1.8  virginica
View(iris) #liat datanya di window baru
str(iris) #informasi dan tipe data
'data.frame':   150 obs. of  5 variables:
 $ Sepal.Length: num  5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
 $ Sepal.Width : num  3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
 $ Petal.Length: num  1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
 $ Petal.Width : num  0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
 $ Species     : Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...

atau kalo mau import data dari file Iris.csv atau Iris.xlsx

df <- read.csv("./Iris.csv") #janlup dikasih tau parameternya path ya jadi bebas

atau pake package readr dan readxl pada R

library(readr)
df <- read_csv("./Iris.csv")
Rows: 150 Columns: 5
── Column specification ────────────────────────────────────────────────────────
Delimiter: ","
chr (1): Species
dbl (4): Sepal.Length, Sepal.Width, Petal.Length, Petal.Width

ℹ Use `spec()` to retrieve the full column specification for this data.
ℹ Specify the column types or set `show_col_types = FALSE` to quiet this message.
library(readxl)
df_excel <- read_excel("./Iris.xlsx")
#cara manual agak ribet sehingga direkomendasikan pake fitur import dataset di Rstudio saja

Statistik deskriptif sederhana

deskriptif yg simple dulu

View(df)
dim(df) #cek dimensi
[1] 150   5
ls(df) #cek nama kolom
[1] "Petal.Length" "Petal.Width"  "Sepal.Length" "Sepal.Width"  "Species"     

deskriptif setiap kolom

mean(df$Sepal.Length)
[1] 5.843333
median(df$Sepal.Length)
[1] 5.8
sum(df$Sepal.Length)
[1] 876.5
sd(df$Sepal.Length)
[1] 0.8280661
var(df$Sepal.Length)
[1] 0.6856935
length(df$Sepal.Length)
[1] 150
standarerror <- sd(df$Sepal.Length)/sqrt(length(df$Sepal.Length))
sort(df$Sepal.Length)
  [1] 4.3 4.4 4.4 4.4 4.5 4.6 4.6 4.6 4.6 4.7 4.7 4.8 4.8 4.8 4.8 4.8 4.9 4.9
 [19] 4.9 4.9 4.9 4.9 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.1 5.1 5.1 5.1
 [37] 5.1 5.1 5.1 5.1 5.1 5.2 5.2 5.2 5.2 5.3 5.4 5.4 5.4 5.4 5.4 5.4 5.5 5.5
 [55] 5.5 5.5 5.5 5.5 5.5 5.6 5.6 5.6 5.6 5.6 5.6 5.7 5.7 5.7 5.7 5.7 5.7 5.7
 [73] 5.7 5.8 5.8 5.8 5.8 5.8 5.8 5.8 5.9 5.9 5.9 6.0 6.0 6.0 6.0 6.0 6.0 6.1
 [91] 6.1 6.1 6.1 6.1 6.1 6.2 6.2 6.2 6.2 6.3 6.3 6.3 6.3 6.3 6.3 6.3 6.3 6.3
[109] 6.4 6.4 6.4 6.4 6.4 6.4 6.4 6.5 6.5 6.5 6.5 6.5 6.6 6.6 6.7 6.7 6.7 6.7
[127] 6.7 6.7 6.7 6.7 6.8 6.8 6.8 6.9 6.9 6.9 6.9 7.0 7.1 7.2 7.2 7.2 7.3 7.4
[145] 7.6 7.7 7.7 7.7 7.7 7.9
min(df$Sepal.Length)
[1] 4.3
max(df$Sepal.Length)
[1] 7.9
range(df$Sepal.Length)
[1] 4.3 7.9
library(DescTools)
Mode(df$Sepal.Length) #package DescTools
[1] 5
attr(,"freq")
[1] 10
plot(density(df$Sepal.Length))

summary(df$Sepal.Length)
   Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
  4.300   5.100   5.800   5.843   6.400   7.900 
#alternatif
library(psych)

Attaching package: 'psych'
The following objects are masked from 'package:DescTools':

    AUC, ICC, SD
describe(df$Sepal.Length)
   vars   n mean   sd median trimmed  mad min max range skew kurtosis   se
X1    1 150 5.84 0.83    5.8    5.81 1.04 4.3 7.9   3.6 0.31    -0.61 0.07
#kalo dari 1 kolom doang, skrg langsung keseluruhan variabel dalam data
summary(df) #khusus numerik
  Sepal.Length    Sepal.Width     Petal.Length    Petal.Width   
 Min.   :4.300   Min.   :2.000   Min.   :1.000   Min.   :0.100  
 1st Qu.:5.100   1st Qu.:2.800   1st Qu.:1.600   1st Qu.:0.300  
 Median :5.800   Median :3.000   Median :4.350   Median :1.300  
 Mean   :5.843   Mean   :3.057   Mean   :3.758   Mean   :1.199  
 3rd Qu.:6.400   3rd Qu.:3.300   3rd Qu.:5.100   3rd Qu.:1.800  
 Max.   :7.900   Max.   :4.400   Max.   :6.900   Max.   :2.500  
   Species         
 Length:150        
 Class :character  
 Mode  :character  
                   
                   
                   
describe(df)
             vars   n mean   sd median trimmed  mad min max range  skew
Sepal.Length    1 150 5.84 0.83   5.80    5.81 1.04 4.3 7.9   3.6  0.31
Sepal.Width     2 150 3.06 0.44   3.00    3.04 0.44 2.0 4.4   2.4  0.31
Petal.Length    3 150 3.76 1.77   4.35    3.76 1.85 1.0 6.9   5.9 -0.27
Petal.Width     4 150 1.20 0.76   1.30    1.18 1.04 0.1 2.5   2.4 -0.10
Species*        5 150 2.00 0.82   2.00    2.00 1.48 1.0 3.0   2.0  0.00
             kurtosis   se
Sepal.Length    -0.61 0.07
Sepal.Width      0.14 0.04
Petal.Length    -1.42 0.14
Petal.Width     -1.36 0.06
Species*        -1.52 0.07

Scatter

plot paling dasar: semua variabel numerik menjadi scatter

plot(df)

plot(df$Sepal.Length, df$Sepal.Width)

tambahkan judul pake main

plot(df$Sepal.Length, df$Sepal.Width, 
     main = "Ini Judul grafiknya")

tambahkan label sumbu

plot(df$Sepal.Length, df$Sepal.Width, 
     main = "Ini Judul grafiknya",
     xlab = "Sumbu X",
     ylab = "Sumbu Y")

Histogram

hist(df$Sepal.Length) #standar

hist(df$Sepal.Length, main = "Judul", xlab = "Nilai Sepal Length")

hist(df$Sepal.Length, main = "Judul", xlab = "Nilai Sepal Length", freq = FALSE)

hist(df$Sepal.Length,
     main = "Judul",
     xlab = "Nilai Sepal Length",
     freq = FALSE,
     breaks = 20)

hist(df$Sepal.Length,
     main = "Judul",
     xlab = "Nilai Sepal Length",
     freq = FALSE,
     breaks = 20,
     xlim = c(min(df$Sepal.Length),max(df$Sepal.Length)),
     col = "yellow")

hist(df$Sepal.Length, prob = TRUE)
grid(lty = 2, col = "gray", lwd = 1)
grid(nx = NA, ny = NULL, lty = 2, col = "gray", lwd = 1)

lines(density(df$Sepal.Length), lwd = 2, col = 'red')

Boxplot

boxplot(df$Sepal.Length) #1 variabel

boxplot(df$Sepal.Length, df$Sepal.Width) #2 variabel atau lebih

boxplot(df$Sepal.Length, df$Sepal.Width,
        main = "Boxplot Perbandingan Sepal Length dan Sepal Width",
        names = c("Sepal Length", "Sepal Width")) #tambahkan judul dan xlabel

boxplot(df$Sepal.Length, df$Sepal.Width,
        main = "Boxplot Perbandingan Sepal Length dan Sepal Width",
        names = c("Sepal Length", "Sepal Width"),
        col = c("red", "blue")) #ganti warna

boxplot(df$Sepal.Length, df$Sepal.Width,
        main = "Boxplot Perbandingan Sepal Length dan Sepal Width",
        names = c("Sepal Length", "Sepal Width"),
        col = c("red", "blue"),
        horizontal = TRUE) #rotate jadi horizontal

boxplot(df$Sepal.Length ~ df$Species)

boxplot(Sepal.Length ~ Species, data = df)

boxplot(df$Sepal.Length ~ df$Species, 
        main = "Perbandingan Sepal Length berdasarkan Species",
        xlab = "Species",
        ylab = "Sepal Length",
        col = c("blue","yellow","red"),
        notch = TRUE)

Barchart

dummy <- data.frame(name=letters[1:5],
                    value=sample(seq(4,15),5))
barplot(height = dummy$value,
        names.arg = dummy$name,
        horiz = F,
        col = "violet",
        width = 1, space = 2, density = 10,
        font.axis = 2,
        col.axis = "red",
        cex.axis = 1)

counts <- table(df$Species)
barplot(counts,
        main = "Persebaran Spesies",
        xlab = "Spesies", ylab = "Counts")

Piechart

pie(counts, 
    labels = counts, 
    col = rainbow(6),
    main = "Persebaran Spesies")

pielabels <- round(counts/sum(counts)*100, 2)
pie(counts, 
    labels = paste0(pielabels, "%"), 
    col = rainbow(6),
    main = "Persebaran Spesies")
legend("topleft", legend = c("setosa","versicolor", "virginica"),
       fill = rainbow(6), cex = 0.8)

Line chart

plot(df$Sepal.Length, type = 'l')

plot(df$Sepal.Length, type = 'l', main = "Pergerakan Sepal Length per Waktu",
     xlab = "Unit Waktu",
     ylab = "Sepal Length",
     col = "darkgreen",
     lty = 1,
     lwd = 2)
lines(df$Sepal.Width, type = "l")

plot(df$Sepal.Length, type = 'l', main = "Perbandingan Pertumbuhan Panjang dan Lebar Kelopak",
     xlab = "Unit Waktu",
     ylab = "Pengukuran",
     col = "darkgreen",
     lty = 1,
     lwd = 2,
     ylim = c(min(df$Sepal.Length, df$Sepal.Width),
              max(df$Sepal.Length, df$Sepal.Width)))
              
lines(df$Sepal.Width,
      type = "l",
      col = "blue", lwd = 2)
      
legend("topleft",
       legend = c("Panjang", "Lebar"),
       col = c("darkgreen", "blue"),
       lty = 1, lwd = 2, 
       bty = "n")
       
legend(-10,8,
       legend = c("Panjang", "Lebar"),
       col = c("darkgreen", "blue"),
       lty = 1, lwd = 2, 
       bty = "n")