library(dplyr)
## 
## Attaching package: 'dplyr'
## The following objects are masked from 'package:stats':
## 
##     filter, lag
## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union
library (ggplot2)
MAHASISWA <- read.csv("df_mahasiswa.csv")
MAHASISWA
##     X id_mahasiswa jenis_kelamin jam_belajar_per_hari frekuensi_login_lms
## 1   1       MHS001             L                    4                   1
## 2   2       MHS002             P                    4                   2
## 3   3       MHS003             P                    2                   6
## 4   4       MHS004             P                    5                   3
## 5   5       MHS005             L                    3                   2
## 6   6       MHS006             L                    3                   7
## 7   7       MHS007             P                    1                   7
## 8   8       MHS008             L                    3                   4
## 9   9       MHS009             P                    2                   6
## 10 10       MHS010             L                    1                   5
## 11 11       MHS011             L                    1                   1
## 12 12       MHS012             P                    1                   2
## 13 13       MHS013             P                    2                   6
## 14 14       MHS014             L                    4                   2
## 15 15       MHS015             L                    1                   2
## 16 16       MHS016             L                    5                   1
## 17 17       MHS017             L                    2                   7
## 18 18       MHS018             L                    5                   7
## 19 19       MHS019             L                    5                   2
## 20 20       MHS020             L                    3                   1
## 21 21       MHS021             L                    1                   6
## 22 22       MHS022             P                    4                   7
## 23 23       MHS023             L                    4                   4
## 24 24       MHS024             P                    5                   4
## 25 25       MHS025             L                    3                   1
## 26 26       MHS026             L                    4                   6
## 27 27       MHS027             L                    2                   3
## 28 28       MHS028             P                    2                   6
## 29 29       MHS029             L                    2                   2
## 30 30       MHS030             P                    5                   3
## 31 31       MHS031             P                    2                   7
## 32 32       MHS032             L                    1                   2
## 33 33       MHS033             P                    1                   7
## 34 34       MHS034             P                    5                   4
## 35 35       MHS035             L                    4                   1
## 36 36       MHS036             P                    3                   1
## 37 37       MHS037             L                    4                   6
## 38 38       MHS038             L                    4                   1
## 39 39       MHS039             P                    1                   1
## 40 40       MHS040             L                    4                   2
## 41 41       MHS041             L                    5                   7
## 42 42       MHS042             P                    4                   6
## 43 43       MHS043             P                    4                   5
## 44 44       MHS044             P                    2                   7
## 45 45       MHS045             P                    5                   2
## 46 46       MHS046             L                    1                   3
## 47 47       MHS047             L                    4                   5
## 48 48       MHS048             L                    5                   4
## 49 49       MHS049             P                    4                   5
## 50 50       MHS050             P                    2                   4
## 51 51       MHS051             L                    4                   6
## 52 52       MHS052             L                    4                   4
## 53 53       MHS053             L                    3                   4
## 54 54       MHS054             L                    5                   4
## 55 55       MHS055             P                    2                   7
##    motivasi_belajar  ipk
## 1                82 3.12
## 2                73 3.45
## 3                71 3.07
## 4                98 3.43
## 5                81 2.83
## 6                61 3.10
## 7                44 2.98
## 8                69 3.08
## 9                44 2.82
## 10               46 2.93
## 11               56 2.64
## 12               35 2.71
## 13               59 3.11
## 14               81 3.31
## 15               44 2.90
## 16               90 3.46
## 17               52 3.06
## 18               92 3.89
## 19               84 3.09
## 20               73 2.73
## 21               47 2.96
## 22               72 3.69
## 23               83 3.54
## 24               81 3.61
## 25               70 2.65
## 26               89 3.32
## 27               59 2.94
## 28               53 3.14
## 29               48 2.89
## 30               87 3.40
## 31               71 3.22
## 32               39 2.66
## 33               46 3.11
## 34               87 3.56
## 35               91 3.13
## 36               66 2.95
## 37               68 3.67
## 38               90 3.29
## 39               52 2.52
## 40               80 3.17
## 41               90 3.73
## 42               73 3.05
## 43               91 3.29
## 44               63 3.15
## 45               96 3.33
## 46               43 2.49
## 47               82 3.13
## 48               92 3.70
## 49               73 3.22
## 50               57 3.05
## 51               92 3.65
## 52               88 3.30
## 53               80 3.29
## 54              100 3.41
## 55               71 3.21
MAHASISWA_selected <- select(MAHASISWA, id_mahasiswa, jenis_kelamin, jam_belajar_per_hari, frekuensi_login_lms, motivasi_belajar, ipk )
head(MAHASISWA_selected)
##   id_mahasiswa jenis_kelamin jam_belajar_per_hari frekuensi_login_lms
## 1       MHS001             L                    4                   1
## 2       MHS002             P                    4                   2
## 3       MHS003             P                    2                   6
## 4       MHS004             P                    5                   3
## 5       MHS005             L                    3                   2
## 6       MHS006             L                    3                   7
##   motivasi_belajar  ipk
## 1               82 3.12
## 2               73 3.45
## 3               71 3.07
## 4               98 3.43
## 5               81 2.83
## 6               61 3.10
str(MAHASISWA)
## 'data.frame':    55 obs. of  7 variables:
##  $ X                   : int  1 2 3 4 5 6 7 8 9 10 ...
##  $ id_mahasiswa        : chr  "MHS001" "MHS002" "MHS003" "MHS004" ...
##  $ jenis_kelamin       : chr  "L" "P" "P" "P" ...
##  $ jam_belajar_per_hari: int  4 4 2 5 3 3 1 3 2 1 ...
##  $ frekuensi_login_lms : int  1 2 6 3 2 7 7 4 6 5 ...
##  $ motivasi_belajar    : int  82 73 71 98 81 61 44 69 44 46 ...
##  $ ipk                 : num  3.12 3.45 3.07 3.43 2.83 3.1 2.98 3.08 2.82 2.93 ...
colSums(is.na(MAHASISWA))
##                    X         id_mahasiswa        jenis_kelamin 
##                    0                    0                    0 
## jam_belajar_per_hari  frekuensi_login_lms     motivasi_belajar 
##                    0                    0                    0 
##                  ipk 
##                    0
summary(MAHASISWA)
##        X        id_mahasiswa       jenis_kelamin      jam_belajar_per_hari
##  Min.   : 1.0   Length:55          Length:55          Min.   :1.000       
##  1st Qu.:14.5   Class :character   Class :character   1st Qu.:2.000       
##  Median :28.0   Mode  :character   Mode  :character   Median :3.000       
##  Mean   :28.0                                         Mean   :3.127       
##  3rd Qu.:41.5                                         3rd Qu.:4.000       
##  Max.   :55.0                                         Max.   :5.000       
##  frekuensi_login_lms motivasi_belajar      ipk       
##  Min.   :1.000       Min.   : 35.0    Min.   :2.490  
##  1st Qu.:2.000       1st Qu.: 56.5    1st Qu.:2.955  
##  Median :4.000       Median : 73.0    Median :3.130  
##  Mean   :4.018       Mean   : 71.0    Mean   :3.166  
##  3rd Qu.:6.000       3rd Qu.: 87.0    3rd Qu.:3.365  
##  Max.   :7.000       Max.   :100.0    Max.   :3.890
aggregate(ipk ~ jenis_kelamin, data = MAHASISWA, mean)
##   jenis_kelamin      ipk
## 1             L 3.158125
## 2             P 3.176957
sort(table(MAHASISWA$motivasi_belajar), decreasing = TRUE)[1]
## 73 
##  4
tertinggi <- MAHASISWA[which.max(MAHASISWA$ipk), ]
tertinggi
##     X id_mahasiswa jenis_kelamin jam_belajar_per_hari frekuensi_login_lms
## 18 18       MHS018             L                    5                   7
##    motivasi_belajar  ipk
## 18               92 3.89
terpilih <- subset(MAHASISWA, ipk > 3.5 & motivasi_belajar > 85)
terpilih
##     X id_mahasiswa jenis_kelamin jam_belajar_per_hari frekuensi_login_lms
## 18 18       MHS018             L                    5                   7
## 34 34       MHS034             P                    5                   4
## 41 41       MHS041             L                    5                   7
## 48 48       MHS048             L                    5                   4
## 51 51       MHS051             L                    4                   6
##    motivasi_belajar  ipk
## 18               92 3.89
## 34               87 3.56
## 41               90 3.73
## 48               92 3.70
## 51               92 3.65
max_login <- max(MAHASISWA$frekuensi_login_lms, na.rm = TRUE)

mahasiswa_login_tertinggi <- subset(MAHASISWA, frekuensi_login_lms == max_login)

mahasiswa_login_tertinggi$ipk_tinggi <- mahasiswa_login_tertinggi$ipk > 3.5

mahasiswa_login_tertinggi[, c("id_mahasiswa", "frekuensi_login_lms", "ipk", "ipk_tinggi")]
##    id_mahasiswa frekuensi_login_lms  ipk ipk_tinggi
## 6        MHS006                   7 3.10      FALSE
## 7        MHS007                   7 2.98      FALSE
## 17       MHS017                   7 3.06      FALSE
## 18       MHS018                   7 3.89       TRUE
## 22       MHS022                   7 3.69       TRUE
## 31       MHS031                   7 3.22      FALSE
## 33       MHS033                   7 3.11      FALSE
## 41       MHS041                   7 3.73       TRUE
## 44       MHS044                   7 3.15      FALSE
## 55       MHS055                   7 3.21      FALSE
mahasiswa_4jam_lebih <- subset(MAHASISWA, jam_belajar_per_hari >= 4)
mahasiswa_kurang_4jam <- subset(MAHASISWA, jam_belajar_per_hari < 4)

rata_ipk_4jam_lebih <- mean(mahasiswa_4jam_lebih$ipk, na.rm = TRUE)
rata_ipk_kurang_4jam <- mean(mahasiswa_kurang_4jam$ipk, na.rm = TRUE)

rata_ipk_4jam_lebih
## [1] 3.405185
rata_ipk_kurang_4jam
## [1] 2.935357