BAB 1 Pendahuluan

Latar Belakang

(Tuliskan latar belakang di sini…)

Rumusan Masalah

  1. Apa saja faktor utama yang mempengaruhi tingkat dropout mahasiswa di perguruan tinggi?
  2. Bagaimana penerapan metode Principal Component Analysis (PCA) dalam mereduksi dimensi data akademik mahasiswa?
  3. Bagaimana penggunaan Factor Analysis (FA) untuk mengidentifikasi faktor-faktor laten yang berkontribusi terhadap kesuksesan akademik mahasiswa?

Tujuan Penelitian

  1. Mengidentifikasi faktor-faktor utama yang berpengaruh terhadap tingkat dropout mahasiswa di perguruan tinggi.
  2. Menganalisis efektivitas metode Principal Component Analysis (PCA) dalam mereduksi dimensi data akademik mahasiswa.
  3. Menggunakan Factor Analysis (FA) untuk menemukan faktor laten yang berkontribusi terhadap kesuksesan akademik mahasiswa.

BAB 2 Metodologi Penelitian

Data

Dataset yang digunakan dalam penelitian ini berasal dari [https://archive.ics.uci.edu/dataset/697/predict+students+dropout+and+academic+success].

setwd("D:/analisis multivariat_smt4")
dataset <- read.csv("quantitative_features.csv")

Variabel

VARIABEL NAMA FITUR KETERANGAN
X1 Previous qualification (grade) Nilai pendidikan terakhir
X2 Admission grade Nilai masuk universitas mahasiswa
X3 Age at enrollment Usia mahasiswa saat pertama kali masuk kuliah
X4 Curricular units 1st sem (credited) Mata kuliah yang dikonversi (semester 1)
X5 Curricular units 1st sem (enrolled) Mata kuliah yang diambil (semester 1)
X6 Curricular units 1st sem (evaluations) Mata kuliah yang dievaluasi (semester 1)
X7 Curricular units 1st sem (approved) Mata kuliah yang lulus (semester 1)
X8 Curricular units 1st sem (grade) Nilai rata-rata mata kuliah (semester 1)
X9 Curricular units 1st sem (without evaluations) Mata kuliah tanpa evaluasi (semester 1)
X10 Curricular units 2nd sem (credited) Mata kuliah yang dikonversi (semester 2)
X11 Curricular units 2nd sem (enrolled) Mata kuliah yang diambil (semester 2)
X12 Curricular units 2nd sem (evaluations) Mata kuliah yang dievaluasi (semester 2)
X13 Curricular units 2nd sem (approved) Mata kuliah yang lulus (semester 2)
X14 Curricular units 2nd sem (grade) Nilai rata-rata mata kuliah (semester 2)
X15 Curricular units 2nd sem (without evaluations) Mata kuliah tanpa evaluasi (semester 2)
X16 Unemployment rate Tingkat pengangguran negara tempat mahasiswa kuliah
X17 Inflation rate Tingkat inflasi negara tempat mahasiswa kuliah
X18 GDP Produk domestik bruto (PDB) negara tempat mahasiswa kuliah

BAB 3 Pembahasan

A. Statistik Deskriptif

str(dataset)  # Melihat struktur data
## 'data.frame':    4424 obs. of  18 variables:
##  $ Previous.qualification..grade.                : num  122 160 122 122 100 ...
##  $ Admission.grade                               : num  127 142 125 120 142 ...
##  $ Age.at.enrollment                             : int  20 19 19 20 45 50 18 22 21 18 ...
##  $ Curricular.units.1st.sem..credited.           : int  0 0 0 0 0 0 0 0 0 0 ...
##  $ Curricular.units.1st.sem..enrolled.           : int  0 6 6 6 6 5 7 5 6 6 ...
##  $ Curricular.units.1st.sem..evaluations.        : int  0 6 0 8 9 10 9 5 8 9 ...
##  $ Curricular.units.1st.sem..approved.           : int  0 6 0 6 5 5 7 0 6 5 ...
##  $ Curricular.units.1st.sem..grade.              : num  0 14 0 13.4 12.3 ...
##  $ Curricular.units.1st.sem..without.evaluations.: int  0 0 0 0 0 0 0 0 0 0 ...
##  $ Curricular.units.2nd.sem..credited.           : int  0 0 0 0 0 0 0 0 0 0 ...
##  $ Curricular.units.2nd.sem..enrolled.           : int  0 6 6 6 6 5 8 5 6 6 ...
##  $ Curricular.units.2nd.sem..evaluations.        : int  0 6 0 10 6 17 8 5 7 14 ...
##  $ Curricular.units.2nd.sem..approved.           : int  0 6 0 5 6 5 8 0 6 2 ...
##  $ Curricular.units.2nd.sem..grade.              : num  0 13.7 0 12.4 13 ...
##  $ Curricular.units.2nd.sem..without.evaluations.: int  0 0 0 0 0 5 0 0 0 0 ...
##  $ Unemployment.rate                             : num  10.8 13.9 10.8 9.4 13.9 16.2 15.5 15.5 16.2 8.9 ...
##  $ Inflation.rate                                : num  1.4 -0.3 1.4 -0.8 -0.3 0.3 2.8 2.8 0.3 1.4 ...
##  $ GDP                                           : num  1.74 0.79 1.74 -3.12 0.79 -0.92 -4.06 -4.06 -0.92 3.51 ...
summary(dataset)  # Statistik ringkasan
##  Previous.qualification..grade. Admission.grade Age.at.enrollment
##  Min.   : 95.0                  Min.   : 95.0   Min.   :17.00    
##  1st Qu.:125.0                  1st Qu.:117.9   1st Qu.:19.00    
##  Median :133.1                  Median :126.1   Median :20.00    
##  Mean   :132.6                  Mean   :127.0   Mean   :23.27    
##  3rd Qu.:140.0                  3rd Qu.:134.8   3rd Qu.:25.00    
##  Max.   :190.0                  Max.   :190.0   Max.   :70.00    
##  Curricular.units.1st.sem..credited. Curricular.units.1st.sem..enrolled.
##  Min.   : 0.00                       Min.   : 0.000                     
##  1st Qu.: 0.00                       1st Qu.: 5.000                     
##  Median : 0.00                       Median : 6.000                     
##  Mean   : 0.71                       Mean   : 6.271                     
##  3rd Qu.: 0.00                       3rd Qu.: 7.000                     
##  Max.   :20.00                       Max.   :26.000                     
##  Curricular.units.1st.sem..evaluations. Curricular.units.1st.sem..approved.
##  Min.   : 0.000                         Min.   : 0.000                     
##  1st Qu.: 6.000                         1st Qu.: 3.000                     
##  Median : 8.000                         Median : 5.000                     
##  Mean   : 8.299                         Mean   : 4.707                     
##  3rd Qu.:10.000                         3rd Qu.: 6.000                     
##  Max.   :45.000                         Max.   :26.000                     
##  Curricular.units.1st.sem..grade.
##  Min.   : 0.00                   
##  1st Qu.:11.00                   
##  Median :12.29                   
##  Mean   :10.64                   
##  3rd Qu.:13.40                   
##  Max.   :18.88                   
##  Curricular.units.1st.sem..without.evaluations.
##  Min.   : 0.0000                               
##  1st Qu.: 0.0000                               
##  Median : 0.0000                               
##  Mean   : 0.1377                               
##  3rd Qu.: 0.0000                               
##  Max.   :12.0000                               
##  Curricular.units.2nd.sem..credited. Curricular.units.2nd.sem..enrolled.
##  Min.   : 0.0000                     Min.   : 0.000                     
##  1st Qu.: 0.0000                     1st Qu.: 5.000                     
##  Median : 0.0000                     Median : 6.000                     
##  Mean   : 0.5418                     Mean   : 6.232                     
##  3rd Qu.: 0.0000                     3rd Qu.: 7.000                     
##  Max.   :19.0000                     Max.   :23.000                     
##  Curricular.units.2nd.sem..evaluations. Curricular.units.2nd.sem..approved.
##  Min.   : 0.000                         Min.   : 0.000                     
##  1st Qu.: 6.000                         1st Qu.: 2.000                     
##  Median : 8.000                         Median : 5.000                     
##  Mean   : 8.063                         Mean   : 4.436                     
##  3rd Qu.:10.000                         3rd Qu.: 6.000                     
##  Max.   :33.000                         Max.   :20.000                     
##  Curricular.units.2nd.sem..grade.
##  Min.   : 0.00                   
##  1st Qu.:10.75                   
##  Median :12.20                   
##  Mean   :10.23                   
##  3rd Qu.:13.33                   
##  Max.   :18.57                   
##  Curricular.units.2nd.sem..without.evaluations. Unemployment.rate
##  Min.   : 0.0000                                Min.   : 7.60    
##  1st Qu.: 0.0000                                1st Qu.: 9.40    
##  Median : 0.0000                                Median :11.10    
##  Mean   : 0.1503                                Mean   :11.57    
##  3rd Qu.: 0.0000                                3rd Qu.:13.90    
##  Max.   :12.0000                                Max.   :16.20    
##  Inflation.rate        GDP           
##  Min.   :-0.800   Min.   :-4.060000  
##  1st Qu.: 0.300   1st Qu.:-1.700000  
##  Median : 1.400   Median : 0.320000  
##  Mean   : 1.228   Mean   : 0.001969  
##  3rd Qu.: 2.600   3rd Qu.: 1.790000  
##  Max.   : 3.700   Max.   : 3.510000
head(dataset)  # Melihat beberapa baris pertama
##   Previous.qualification..grade. Admission.grade Age.at.enrollment
## 1                          122.0           127.3                20
## 2                          160.0           142.5                19
## 3                          122.0           124.8                19
## 4                          122.0           119.6                20
## 5                          100.0           141.5                45
## 6                          133.1           114.8                50
##   Curricular.units.1st.sem..credited. Curricular.units.1st.sem..enrolled.
## 1                                   0                                   0
## 2                                   0                                   6
## 3                                   0                                   6
## 4                                   0                                   6
## 5                                   0                                   6
## 6                                   0                                   5
##   Curricular.units.1st.sem..evaluations. Curricular.units.1st.sem..approved.
## 1                                      0                                   0
## 2                                      6                                   6
## 3                                      0                                   0
## 4                                      8                                   6
## 5                                      9                                   5
## 6                                     10                                   5
##   Curricular.units.1st.sem..grade.
## 1                          0.00000
## 2                         14.00000
## 3                          0.00000
## 4                         13.42857
## 5                         12.33333
## 6                         11.85714
##   Curricular.units.1st.sem..without.evaluations.
## 1                                              0
## 2                                              0
## 3                                              0
## 4                                              0
## 5                                              0
## 6                                              0
##   Curricular.units.2nd.sem..credited. Curricular.units.2nd.sem..enrolled.
## 1                                   0                                   0
## 2                                   0                                   6
## 3                                   0                                   6
## 4                                   0                                   6
## 5                                   0                                   6
## 6                                   0                                   5
##   Curricular.units.2nd.sem..evaluations. Curricular.units.2nd.sem..approved.
## 1                                      0                                   0
## 2                                      6                                   6
## 3                                      0                                   0
## 4                                     10                                   5
## 5                                      6                                   6
## 6                                     17                                   5
##   Curricular.units.2nd.sem..grade.
## 1                          0.00000
## 2                         13.66667
## 3                          0.00000
## 4                         12.40000
## 5                         13.00000
## 6                         11.50000
##   Curricular.units.2nd.sem..without.evaluations. Unemployment.rate
## 1                                              0              10.8
## 2                                              0              13.9
## 3                                              0              10.8
## 4                                              0               9.4
## 5                                              0              13.9
## 6                                              5              16.2
##   Inflation.rate   GDP
## 1            1.4  1.74
## 2           -0.3  0.79
## 3            1.4  1.74
## 4           -0.8 -3.12
## 5           -0.3  0.79
## 6            0.3 -0.92
boxplot(dataset, main = "Boxplot Data Awal", las = 2)

sum(is.na(dataset))
## [1] 0
data_scaled <- scale(dataset)

colnames(data_scaled) <- paste0("X", 1:ncol(data_scaled))  # Mengembalikan nama kolom setelah scaling
colnames(data_scaled)
##  [1] "X1"  "X2"  "X3"  "X4"  "X5"  "X6"  "X7"  "X8"  "X9"  "X10" "X11" "X12"
## [13] "X13" "X14" "X15" "X16" "X17" "X18"
correlation_matrix <- cor(data_scaled)
heatmap(correlation_matrix)

B. Asumsi

Uji KMO dan Bartlett

library(psych)
## Warning: package 'psych' was built under R version 4.4.3
r <- cor(dataset)
KMO(r)
## Kaiser-Meyer-Olkin factor adequacy
## Call: KMO(r = r)
## Overall MSA =  0.75
## MSA for each item = 
##                 Previous.qualification..grade. 
##                                           0.52 
##                                Admission.grade 
##                                           0.52 
##                              Age.at.enrollment 
##                                           0.86 
##            Curricular.units.1st.sem..credited. 
##                                           0.72 
##            Curricular.units.1st.sem..enrolled. 
##                                           0.74 
##         Curricular.units.1st.sem..evaluations. 
##                                           0.78 
##            Curricular.units.1st.sem..approved. 
##                                           0.81 
##               Curricular.units.1st.sem..grade. 
##                                           0.78 
## Curricular.units.1st.sem..without.evaluations. 
##                                           0.56 
##            Curricular.units.2nd.sem..credited. 
##                                           0.76 
##            Curricular.units.2nd.sem..enrolled. 
##                                           0.73 
##         Curricular.units.2nd.sem..evaluations. 
##                                           0.80 
##            Curricular.units.2nd.sem..approved. 
##                                           0.77 
##               Curricular.units.2nd.sem..grade. 
##                                           0.78 
## Curricular.units.2nd.sem..without.evaluations. 
##                                           0.55 
##                              Unemployment.rate 
##                                           0.44 
##                                 Inflation.rate 
##                                           0.40 
##                                            GDP 
##                                           0.50
bartlett.test(dataset)
## 
##  Bartlett test of homogeneity of variances
## 
## data:  dataset
## Bartlett's K-squared = 97460, df = 17, p-value < 2.2e-16

C. Principal Component Analysis (PCA)

library(factoextra)
## Warning: package 'factoextra' was built under R version 4.4.3
## Loading required package: ggplot2
## 
## Attaching package: 'ggplot2'
## The following objects are masked from 'package:psych':
## 
##     %+%, alpha
## Welcome! Want to learn more? See two factoextra-related books at https://goo.gl/ve3WBa
colnames(data_scaled) <- paste0("X", 1:ncol(data_scaled))  # Mengembalikan nama kolom setelah scaling
colnames(data_scaled)
##  [1] "X1"  "X2"  "X3"  "X4"  "X5"  "X6"  "X7"  "X8"  "X9"  "X10" "X11" "X12"
## [13] "X13" "X14" "X15" "X16" "X17" "X18"
pca_result <- prcomp(data_scaled, center = TRUE, scale. = TRUE)
summary(pca_result)
## Importance of components:
##                           PC1    PC2     PC3     PC4     PC5     PC6     PC7
## Standard deviation     2.4844 1.5011 1.27133 1.23484 1.14573 1.00481 0.93463
## Proportion of Variance 0.3429 0.1252 0.08979 0.08471 0.07293 0.05609 0.04853
## Cumulative Proportion  0.3429 0.4681 0.55788 0.64260 0.71553 0.77162 0.82015
##                            PC8     PC9    PC10    PC11    PC12    PC13    PC14
## Standard deviation     0.84767 0.79391 0.66307 0.64104 0.60613 0.46180 0.41598
## Proportion of Variance 0.03992 0.03502 0.02443 0.02283 0.02041 0.01185 0.00961
## Cumulative Proportion  0.86006 0.89508 0.91951 0.94234 0.96275 0.97459 0.98421
##                           PC15    PC16    PC17    PC18
## Standard deviation     0.36779 0.30361 0.18908 0.14515
## Proportion of Variance 0.00751 0.00512 0.00199 0.00117
## Cumulative Proportion  0.99172 0.99684 0.99883 1.00000

Scree Plot

screeplot(pca_result, type = "lines", main = "Scree Plot")

fviz_eig(pca_result, addlabels = TRUE, ylim = c(0, 100))

Biplot

biplot(pca_result, scale = 0)

fviz_pca_biplot(pca_result, geom.ind = "point", addEllipses = TRUE)

Correlation Circle

contrib_circle <- fviz_pca_var(pca_result, col.var = "contrib",
                               gradient.cols = c("#00AFBB", "#E7B800", "#FC4E07"), 
                               repel = TRUE) + 
  ggtitle("Kontribusi Variabel")
plot(contrib_circle)

D. Factor Analysis (FA)

varcov <- cov(data_scaled)
pc <- eigen(varcov)
eigenvalues <- pc$values
num_factors <- sum(eigenvalues > 1)
cat("Jumlah faktor berdasarkan Kaiser's Criterion:", num_factors, "\n")
## Jumlah faktor berdasarkan Kaiser's Criterion: 6
# Faktor Loadings
L = matrix(nrow = ncol(data_scaled), ncol = num_factors)
for (i in 1:num_factors) {
  L[, i] = sqrt(eigenvalues[i]) * pc$vectors[, i]
}
print(L)  # Menampilkan factor loadings
##               [,1]        [,2]         [,3]         [,4]          [,5]
##  [1,]  0.001628836  0.26229234  0.798640479  0.171628682 -0.1632769920
##  [2,] -0.023069755  0.23755105  0.793680847  0.200479284 -0.2161124670
##  [3,] -0.065322040 -0.49346926 -0.045800767  0.236865517  0.0530907912
##  [4,] -0.749600431 -0.41168120  0.061550385  0.363608224 -0.1187676764
##  [5,] -0.906014995 -0.21959923 -0.021002725  0.136166891 -0.0204638848
##  [6,] -0.755046373 -0.22686877 -0.036110313 -0.201738916  0.0911360237
##  [7,] -0.905831794  0.24430283  0.009418594  0.061363972  0.0004624634
##  [8,] -0.628881806  0.59501496 -0.041712425 -0.285720966  0.0658525927
##  [9,] -0.117779391 -0.49222201  0.294106268 -0.624162506 -0.1741372762
## [10,] -0.748464329 -0.41058949  0.059414715  0.354942339 -0.1241307050
## [11,] -0.877328960 -0.13792956 -0.037526957  0.078569481  0.0014532339
## [12,] -0.736062700 -0.06487591 -0.076158420 -0.266279843  0.0543276024
## [13,] -0.844714039  0.34195300  0.009668512  0.002201885  0.0065824409
## [14,] -0.626596024  0.61903247 -0.045244787 -0.267092167  0.0380182617
## [15,] -0.059019734 -0.46247938  0.257760459 -0.645841441 -0.1823201241
## [16,] -0.055315292 -0.03116231  0.248228480  0.023016446  0.7543721260
## [17,]  0.003345442 -0.05792676  0.012266149  0.175632145  0.2126035457
## [18,]  0.014946060  0.22211895 -0.333896557  0.098801890 -0.7153066614
##                [,6]
##  [1,] -0.0490288129
##  [2,]  0.0324265927
##  [3,]  0.0931400705
##  [4,]  0.0368110632
##  [5,] -0.0190637292
##  [6,] -0.0046171452
##  [7,] -0.0002925451
##  [8,] -0.0375226606
##  [9,] -0.0581561407
## [10,]  0.0443705449
## [11,] -0.0039801265
## [12,] -0.0136969929
## [13,]  0.0035796081
## [14,] -0.0345839958
## [15,] -0.0641315779
## [16,]  0.3226885805
## [17,] -0.9342066829
## [18,]  0.0812951487
fa_result <- fa(r = data_scaled, covar = TRUE, nfactors = num_factors, rotate = "promax")
## Loading required namespace: GPArotation
print(fa_result$loadings)
## 
## Loadings:
##     MR1    MR2    MR6    MR3    MR4    MR5   
## X1                               0.630       
## X2                               0.928       
## X3   0.188 -0.313  0.120                     
## X4   1.000 -0.150                            
## X5   0.776  0.156  0.160                     
## X6   0.161         0.757                     
## X7   0.631  0.634                            
## X8  -0.110  0.812  0.286                     
## X9                        1.018              
## X10  1.011 -0.138                            
## X11  0.668  0.239  0.154                     
## X12         0.179  0.797                     
## X13  0.559  0.748 -0.172                     
## X14         0.876  0.144                     
## X15                       0.570              
## X16                                    -0.350
## X17                                          
## X18  0.119               -0.265         1.040
## 
##                  MR1   MR2   MR6   MR3   MR4   MR5
## SS loadings    3.890 2.665 1.431 1.448 1.274 1.233
## Proportion Var 0.216 0.148 0.080 0.080 0.071 0.068
## Cumulative Var 0.216 0.364 0.444 0.524 0.595 0.663

Faktor Diagram

fa.diagram(fa_result)

BAB 4 Kesimpulan

  1. Identifikasi Faktor Utama
    Analisis Faktor (FA) mengungkap enam faktor utama yang memengaruhi dropout dan kesuksesan akademik mahasiswa, yaitu:
    • MR1 (Performa Akademik Semester 1): Faktor ini menunjukkan bahwa mahasiswa yang aktif sejak semester pertama memiliki kecenderungan akademik yang lebih baik.
    • MR2 (Performa Akademik Semester 2 & Faktor Usia): Keberhasilan di semester kedua berhubungan dengan performa sebelumnya, tetapi usia saat masuk kuliah memiliki dampak yang lemah atau negatif.
    • MR3 (Beban Mata Kuliah & Evaluasi Tanpa Nilai): Mahasiswa yang mengambil banyak mata kuliah tanpa evaluasi cenderung menghadapi risiko akademik.
    • MR4 (Faktor Demografi & Penerimaan Mahasiswa): Prestasi akademik sebelumnya (nilai masuk) berkontribusi terhadap kesiapan akademik mahasiswa.
    • MR5 (Faktor Ekonomi Makro): Kondisi ekonomi, seperti pengangguran dan PDB, memengaruhi keberlanjutan studi mahasiswa.
    • MR6 (Mata Kuliah Tanpa Evaluasi & Kinerja Semester 2): Beberapa mahasiswa tetap dapat lulus meskipun memiliki mata kuliah tanpa evaluasi di semester awal.
  2. Implikasi terhadap Dropout
    • Faktor-faktor akademik seperti jumlah mata kuliah yang dikreditkan dan nilai masuk berperan penting dalam keberhasilan mahasiswa.
    • Beban akademik tanpa evaluasi formal dapat meningkatkan risiko dropout.
    • Faktor ekonomi eksternal seperti tingkat pengangguran juga berpotensi memengaruhi tingkat dropout.
  3. Temuan Tambahan
    • X17 (Inflation Rate) tidak masuk ke dalam faktor utama mana pun, menunjukkan bahwa inflasi mungkin tidak berdampak langsung terhadap performa akademik mahasiswa.

Daftar Pustaka