Deskripsi Tugas

Penelitian ini bertujuan untuk menganalisis pengaruh berbagai fitur terhadap klasifikasi data menggunakan metode multinomial logistic regression, yang sesuai untuk permasalahan dengan lebih dari dua kelas. Analisis dilakukan secara bertahap meliputi preprocessing data, eksplorasi data (EDA), normalisasi fitur, pembagian data, pembangunan model, serta evaluasi performa.

Data yang digunakan dalam penelitian ini berasal dari UCI Machine Learning Repository dan dapat diakses melalui URL berikut: https://archive.ics.uci.edu/dataset/602/dry+bean+dataset

Dataset awal terdiri dari 13.611 data, kemudian disederhanakan menjadi 910 data melalui teknik sampling dengan mempertimbangkan keseimbangan jumlah data pada setiap kelas (balanced data). Proses penyeimbangan data ini bertujuan untuk menghindari bias pada model klasifikasi. Selain itu, penggunaan sebagian data juga dilakukan untuk meningkatkan efisiensi komputasi tanpa mengurangi representativitas data secara keseluruhan. Evaluasi model dilakukan menggunakan confusion matrix dan nilai akurasi untuk mengukur kinerja model dalam melakukan klasifikasi.

install.packages(c(
  "tidyverse",
  "caret",
  "nnet",
  "broom",
  "kableExtra",
  "marginaleffects",
  "corrplot"
))
## Installing packages into '/cloud/lib/x86_64-pc-linux-gnu-library/4.5'
## (as 'lib' is unspecified)
library(tidyverse)
## ── Attaching core tidyverse packages ──────────────────────── tidyverse 2.0.0 ──
## ✔ dplyr     1.2.1     ✔ readr     2.2.0
## ✔ forcats   1.0.1     ✔ stringr   1.6.0
## ✔ ggplot2   4.0.3     ✔ tibble    3.3.1
## ✔ lubridate 1.9.5     ✔ tidyr     1.3.2
## ✔ purrr     1.2.2     
## ── Conflicts ────────────────────────────────────────── tidyverse_conflicts() ──
## ✖ dplyr::filter() masks stats::filter()
## ✖ dplyr::lag()    masks stats::lag()
## ℹ Use the conflicted package (<http://conflicted.r-lib.org/>) to force all conflicts to become errors
library(caret)
## Loading required package: lattice
## 
## Attaching package: 'caret'
## 
## The following object is masked from 'package:purrr':
## 
##     lift
library(nnet)
library(broom)
library(kableExtra)
## 
## Attaching package: 'kableExtra'
## 
## The following object is masked from 'package:dplyr':
## 
##     group_rows
library(marginaleffects)
library(corrplot)
## corrplot 0.95 loaded
data <- read.csv("Dry_Bean_Dataset_kcl.csv")
str(data)
## 'data.frame':    910 obs. of  17 variables:
##  $ Area           : int  45890 31877 85998 41536 38273 51714 53607 68404 49101 41285 ...
##  $ Perimeter      : num  808 673 1175 734 746 ...
##  $ MajorAxisLength: num  307 250 441 256 281 ...
##  $ MinorAxisLength: num  191 162 252 207 174 ...
##  $ AspectRation   : num  1.6 1.54 1.75 1.23 1.62 ...
##  $ Eccentricity   : num  0.782 0.761 0.821 0.586 0.785 ...
##  $ ConvexArea     : int  46523 32271 88241 41861 38743 52246 54178 69150 49683 41729 ...
##  $ EquivDiameter  : num  242 201 331 230 221 ...
##  $ Extent         : num  0.779 0.72 0.745 0.793 0.731 ...
##  $ Solidity       : num  0.986 0.988 0.975 0.992 0.988 ...
##  $ roundness      : num  0.883 0.884 0.783 0.968 0.863 ...
##  $ Compactness    : num  0.787 0.805 0.75 0.9 0.786 ...
##  $ ShapeFactor1   : num  0.00669 0.00785 0.00513 0.00615 0.00734 ...
##  $ ShapeFactor2   : num  0.00158 0.00203 0.001 0.00249 0.00173 ...
##  $ ShapeFactor3   : num  0.619 0.647 0.562 0.809 0.618 ...
##  $ ShapeFactor4   : num  0.994 0.999 0.985 0.999 0.998 ...
##  $ Class          : chr  "SIRA" "DERMASON" "CALI" "SEKER" ...
data$Class <- as.factor(data$Class)

Code tersebut digunakan untuk mengubah tipe data pada kolom Class menjadi factor agar model klasifikasi multinomial logistic regression dapat mengenali setiap nilai dalam Class sebagai kategori kelas

Analisis Data Eksploratif

table(data$Class)
## 
## BARBUNYA   BOMBAY     CALI DERMASON    HOROZ    SEKER     SIRA 
##      130      130      130      130      130      130      130
ggplot(data, aes(x = Class, y = Area, fill = Class)) +
  geom_boxplot() +
  theme_minimal() +
  ggtitle("Boxplot Area terhadap Class") +
  theme(
    axis.text.x = element_text(angle = 45, hjust = 1)
  )

Pada hasil boxplot nilai area terhadap untuk setiap kelas kacang terlihat bahwa setiap kelas memiliki rentang dan median yang berbeda. Kelas BOMBAY memiliki nilai area paling besar dibandingkan kelas lainnya, sedangkan DERMASON cenderung memiliki area paling kecil. Beberapa titik di luar box menunjukkan adanya outlier.

numeric_data <- data %>% select(where(is.numeric))
cor_matrix <- cor(numeric_data)

corrplot::corrplot(cor_matrix, tl.col = "black", type = "full", tl.srt = 40, tl.cex = 0.5)

Terlihat bahwa fitur seperti Area, Perimeter, MajorAxisLength, dan ConvexArea memiliki korelasi positif yang kuat. Sementara itu, beberapa fitur seperti Compactness, roundness, dan ShapeFactor menunjukkan korelasi negatif terhadap fitur ukuran.

Preprocessing

colSums(is.na(data))
##            Area       Perimeter MajorAxisLength MinorAxisLength    AspectRation 
##               0               0               0               0               0 
##    Eccentricity      ConvexArea   EquivDiameter          Extent        Solidity 
##               0               0               0               0               0 
##       roundness     Compactness    ShapeFactor1    ShapeFactor2    ShapeFactor3 
##               0               0               0               0               0 
##    ShapeFactor4           Class 
##               0               0
numeric_cols <- sapply(data, is.numeric)
data[numeric_cols] <- scale(data[numeric_cols])
set.seed(123)

trainIndex <- createDataPartition(data$Class, p = 0.8, list = FALSE)
trainData <- data[trainIndex, ]
testData  <- data[-trainIndex, ]

Code tersebut membagi data menjadi 80% data latih dan 20% data uji secara proporsional per kelas, serta menggunakan set.seed agar hasil pembagian selalu konsisten.

Model Multinomial Logistic Regression

fit_full <- multinom(Class ~ ., data = trainData)
## # weights:  126 (102 variable)
## initial  value 1416.622589 
## iter  10 value 252.802669
## iter  20 value 115.449005
## iter  30 value 105.385801
## iter  40 value 102.511380
## iter  50 value 100.987913
## iter  60 value 100.343565
## iter  70 value 99.571003
## iter  80 value 99.152343
## iter  90 value 98.868405
## iter 100 value 98.531609
## final  value 98.531609 
## stopped after 100 iterations

Code ini untuk melatih model multinomial logistic regression dengan Class sebagai target dan semua fitur sebagai prediktor. Output menunjukkan proses iterasi di mana nilai loss terus menurun hingga mencapai nilai akhir, menandakan model berhasil belajar dengan baik dan konvergen setelah 100 iterasi.

fit_null <- multinom(Class ~ 1, data = trainData)
## # weights:  14 (6 variable)
## initial  value 1416.622589 
## final  value 1416.622589 
## converged

1. Uji Serentak atau Uji Indepedensi

LL_full <- logLik(fit_full)
LL_null <- logLik(fit_null)

G <- -2 * (LL_null - LL_full)
df <- attr(LL_full, "df") - attr(LL_null, "df")
p_value_LR <- pchisq(G, df, lower.tail = FALSE)

G
## 'log Lik.' 2636.182 (df=6)
df
## [1] 96
p_value_LR
## 'log Lik.' 0 (df=6)

Berdasarkan output uji independensi (Likelihood Ratio Test) pada model multinomial logistic regression, diperoleh nilai log likelihood model penuh sebesar 2636,182 dan log likelihood model tanpa prediktor sebesar 0, dengan selisih derajat bebas sebesar 96. Perbedaan nilai ini menghasilkan statistik uji yang sangat besar dengan p-value mendekati nol. Hal ini menunjukkan bahwa secara simultan seluruh variabel pengukuran bentuk dan ukuran biji kacang seperti Area, Perimeter, MajorAxisLength, dan variabel lainnya memiliki pengaruh yang signifikan terhadap klasifikasi kelas kacang (BARBUNYA, BOMBAY, CALI, DERMASON, HOROZ, SEKER, dan SIRA). Dengan demikian, variabel-variabel tersebut tidak bersifat independen terhadap kelas, melainkan secara bersama-sama mampu menjelaskan perbedaan antar kelas kacang.

2. Uji Parsial

z <- summary(fit_full)$coefficients / summary(fit_full)$standard.errors
p_value_wald <- (1 - pnorm(abs(z), 0, 1)) * 2

p_value_wald
##          (Intercept)      Area Perimeter MajorAxisLength MinorAxisLength
## BOMBAY     0.9850600 0.8712115 0.7944025       0.8329614       0.9795120
## CALI       0.7443691 0.9544550 0.7845601       0.9778936       0.9772253
## DERMASON   0.8264430 0.9092854 0.9766765       0.9937842       0.9868427
## HOROZ      0.6706138 0.9116665 0.9549015       0.9506926       0.9836990
## SEKER      0.8676446 0.9632608 0.9797685       0.9965548       0.9865039
## SIRA       0.8281760 0.9863091 0.9892249       0.9995873       0.9654756
##          AspectRation Eccentricity ConvexArea EquivDiameter    Extent
## BOMBAY      0.9575725    0.9753327  0.8875809     0.9270677 0.9261813
## CALI        0.9754151    0.9810537  0.9888964     0.9899711 0.3614771
## DERMASON    0.8215736    0.9064562  0.9045654     0.9472776 0.7059211
## HOROZ       0.9547635    0.9542528  0.9315858     0.9643577 0.8764332
## SEKER       0.9153180    0.9444280  0.9603400     0.9743016 0.6237358
## SIRA        0.9197979    0.8898028  0.9781760     0.9233539 0.9077193
##            Solidity roundness Compactness ShapeFactor1 ShapeFactor2
## BOMBAY   0.93133877 0.9555620   0.9802272    0.8031193    0.8393473
## CALI     0.20254718 0.6095197   0.9994495    0.9867236    0.9885591
## DERMASON 0.45089612 0.5131358   0.8793019    0.6935874    0.9371629
## HOROZ    0.15145907 0.9055892   0.9918739    0.7709554    0.8601328
## SEKER    0.02611095 0.8071640   0.9853322    0.9327286    0.8012837
## SIRA     0.28715785 0.5880506   0.9791587    0.8781151    0.9495754
##          ShapeFactor3 ShapeFactor4
## BOMBAY      0.9936069    0.9336279
## CALI        0.9880263    0.4401345
## DERMASON    0.8930959    0.7524359
## HOROZ       0.9654815    0.6077368
## SEKER       0.9886184    0.8370066
## SIRA        0.9541651    0.6242765

Hasil uji parsial (Wald test) menunjukkan bahwa tidak terdapat variabel yang berpengaruh signifikan secara individu terhadap klasifikasi jenis kacang (p-value > 0,05). Hal ini disebabkan oleh adanya hubungan yang kuat antar variabel (multikolinearitas), sehingga pengaruh variabel baru terlihat ketika diuji secara simultan. Hal ini dibuktikan pada uji serentak (Likelihood Ratio Test) yang menunjukkan bahwa model signifikan secara keseluruhan.

3. Log odds

summary(fit_full)
## Call:
## multinom(formula = Class ~ ., data = trainData)
## 
## Coefficients:
##          (Intercept)       Area Perimeter MajorAxisLength MinorAxisLength
## BOMBAY     -3.771418  18.098438  9.327555      13.2787480        3.329248
## CALI       -4.039492 -15.889660 28.687010      -6.5683595        6.719376
## DERMASON  -10.355377  12.582015 -5.781055      -2.0410432       -5.347781
## HOROZ       9.661065  22.228501  4.747476      17.7453050       -5.028911
## SEKER      -7.887765   6.374269 -5.478150      -0.8653203       -5.161402
## SIRA       -8.466779   1.862205 -2.460132      -0.1270451      -12.178400
##          AspectRation Eccentricity ConvexArea EquivDiameter     Extent Solidity
## BOMBAY      10.069340    -8.030504  18.391444      7.741162 -2.7710752 2.850839
## CALI         3.260938     1.975511  -3.526355     -2.062791  0.5443060 3.219666
## DERMASON   -23.642527    -9.952692  12.875069     -3.276164 -0.4094107 1.904882
## HOROZ       -8.330088    12.327349  19.734160      7.609842 -0.1359260 3.069299
## SEKER       10.854157     5.955628   6.771905     -3.094337  0.6470415 7.842781
## SIRA         8.924687    10.162892   2.767951     -7.716734  0.1179685 2.516975
##          roundness Compactness ShapeFactor1 ShapeFactor2 ShapeFactor3
## BOMBAY   10.046636  -1.9509300    27.038543    25.024808    0.6394824
## CALI      7.313039  -0.1881134     2.242464    -2.162460   -3.5164154
## DERMASON 11.571996 -11.6261557    32.868782     9.937028  -21.1220841
## HOROZ     1.509761  -2.2411137    40.537107    33.974062   -8.3741346
## SEKER     4.811833  -1.8052595     6.947026    33.362508   -1.7416148
## SIRA     10.330598   2.3836793    13.768612     9.670580    9.1619888
##          ShapeFactor4
## BOMBAY      -4.146662
## CALI        -4.518708
## DERMASON     1.872320
## HOROZ       -4.199221
## SEKER        1.399030
## SIRA        -2.713007
## 
## Std. Errors:
##          (Intercept)     Area Perimeter MajorAxisLength MinorAxisLength
## BOMBAY     201.40446 111.6362  35.79288         62.9608        129.6399
## CALI        12.38830 278.2133 104.93402        237.0405        235.3735
## DERMASON    47.22750 110.4268 197.73832        261.9917        324.2845
## HOROZ       22.71557 200.3710  83.94785        286.9689        246.1324
## SEKER       47.33102 138.3843 216.02229        200.3994        305.1263
## SIRA        39.00996 108.5210 182.16504        245.5911        281.3637
##          AspectRation Eccentricity ConvexArea EquivDiameter     Extent
## BOMBAY      189.27326    259.71248   130.0981      84.57073 29.9089350
## CALI        105.81439     83.18698   253.3890     164.10891  0.5964644
## DERMASON    104.83493     84.69680   107.3852      49.54432  1.0849923
## HOROZ       146.84781    214.88549   229.8684     170.29634  0.8741651
## SEKER       102.07688     85.43969   136.1818      96.05648  1.3189784
## SIRA         88.63673     73.34983   101.1837      80.20732  1.0177088
##           Solidity roundness Compactness ShapeFactor1 ShapeFactor2 ShapeFactor3
## BOMBAY   33.087504 180.29430    78.71712    108.45257     123.4400     79.80917
## CALI      2.526559  14.31798   272.66177    134.76122     150.8040    234.31295
## DERMASON  2.526630  17.69519    76.56127     83.42514     126.0465    157.17266
## HOROZ     2.139784  12.72944   220.04602    139.24274     192.8098    193.50490
## SEKER     3.525547  19.71366    98.19549     82.29873     132.5560    122.08867
## SIRA      2.364740  19.07200    91.24615     89.78018     152.9189    159.40220
##          ShapeFactor4
## BOMBAY      49.791017
## CALI         5.853505
## DERMASON     5.935788
## HOROZ        8.180726
## SEKER        6.800519
## SIRA         5.539027
## 
## Residual Deviance: 197.0632 
## AIC: 401.0632
tidy(fit_full, conf.int = TRUE) %>%
  kable() %>%
  kable_styling("basic", full_width = FALSE)
y.level term estimate std.error statistic p.value conf.low conf.high
BOMBAY (Intercept) -3.7714181 201.4044645 -0.0187256 0.9850600 -398.5169148 390.974079
BOMBAY Area 18.0984381 111.6362264 0.1621198 0.8712115 -200.7045450 236.901421
BOMBAY Perimeter 9.3275552 35.7928834 0.2605980 0.7944025 -60.8252071 79.480317
BOMBAY MajorAxisLength 13.2787480 62.9607994 0.2109050 0.8329614 -110.1221513 136.679647
BOMBAY MinorAxisLength 3.3292482 129.6399125 0.0256807 0.9795120 -250.7603112 257.418808
BOMBAY AspectRation 10.0693404 189.2732648 0.0532000 0.9575725 -360.8994418 381.038123
BOMBAY Eccentricity -8.0305041 259.7124767 -0.0309207 0.9753327 -517.0576048 500.996597
BOMBAY ConvexArea 18.3914441 130.0981447 0.1413659 0.8875809 -236.5962340 273.379122
BOMBAY EquivDiameter 7.7411619 84.5707289 0.0915348 0.9270677 -158.0144208 173.496745
BOMBAY Extent -2.7710752 29.9089350 -0.0926504 0.9261813 -61.3915107 55.849360
BOMBAY Solidity 2.8508386 33.0875041 0.0861606 0.9313388 -61.9994778 67.701155
BOMBAY roundness 10.0466364 180.2942967 0.0557235 0.9555620 -343.3236919 363.416965
BOMBAY Compactness -1.9509300 78.7171191 -0.0247841 0.9802272 -156.2336484 152.331788
BOMBAY ShapeFactor1 27.0385432 108.4525683 0.2493122 0.8031193 -185.5245846 239.601671
BOMBAY ShapeFactor2 25.0248084 123.4400233 0.2027285 0.8393473 -216.9131915 266.962808
BOMBAY ShapeFactor3 0.6394824 79.8091723 0.0080126 0.9936069 -155.7836209 157.062586
BOMBAY ShapeFactor4 -4.1466617 49.7910172 -0.0832813 0.9336279 -101.7352622 93.441939
CALI (Intercept) -4.0394924 12.3883031 -0.3260731 0.7443691 -28.3201203 20.241135
CALI Area -15.8896597 278.2132912 -0.0571132 0.9544550 -561.1776905 529.398371
CALI Perimeter 28.6870098 104.9340232 0.2733814 0.7845601 -176.9798964 234.353916
CALI MajorAxisLength -6.5683595 237.0405191 -0.0277099 0.9778936 -471.1592397 458.022521
CALI MinorAxisLength 6.7193763 235.3735334 0.0285477 0.9772253 -454.6042722 468.043025
CALI AspectRation 3.2609381 105.8143875 0.0308175 0.9754151 -204.1314505 210.653327
CALI Eccentricity 1.9755109 83.1869779 0.0237478 0.9810537 -161.0679698 165.018991
CALI ConvexArea -3.5263548 253.3889609 -0.0139168 0.9888964 -500.1595922 493.106883
CALI EquivDiameter -2.0627905 164.1089122 -0.0125696 0.9899711 -323.7103480 319.584767
CALI Extent 0.5443060 0.5964644 0.9125541 0.3614771 -0.6247427 1.713355
CALI Solidity 3.2196655 2.5265594 1.2743281 0.2025472 -1.7322999 8.171631
CALI roundness 7.3130386 14.3179777 0.5107592 0.6095197 -20.7496821 35.375759
CALI Compactness -0.1881134 272.6617748 -0.0006899 0.9994495 -534.5953720 534.219145
CALI ShapeFactor1 2.2424643 134.7612185 0.0166403 0.9867236 -261.8846705 266.369599
CALI ShapeFactor2 -2.1624600 150.8039657 -0.0143395 0.9885591 -297.7328014 293.407881
CALI ShapeFactor3 -3.5164154 234.3129457 -0.0150073 0.9880263 -462.7613501 455.728519
CALI ShapeFactor4 -4.5187081 5.8535055 -0.7719662 0.4401345 -15.9913680 6.953952
DERMASON (Intercept) -10.3553773 47.2274958 -0.2192659 0.8264430 -102.9195682 82.208814
DERMASON Area 12.5820149 110.4267818 0.1139399 0.9092854 -203.8505004 229.014530
DERMASON Perimeter -5.7810551 197.7383223 -0.0292359 0.9766765 -393.3410451 381.778935
DERMASON MajorAxisLength -2.0410432 261.9917440 -0.0077905 0.9937842 -515.5354257 511.453339
DERMASON MinorAxisLength -5.3477810 324.2844503 -0.0164910 0.9868427 -640.9336243 630.238062
DERMASON AspectRation -23.6425269 104.8349324 -0.2255215 0.8215736 -229.1152189 181.830165
DERMASON Eccentricity -9.9526916 84.6967995 -0.1175097 0.9064562 -175.9553682 156.049985
DERMASON ConvexArea 12.8750686 107.3851748 0.1198961 0.9045654 -197.5960066 223.346144
DERMASON EquivDiameter -3.2761644 49.5443247 -0.0661259 0.9472776 -100.3812564 93.828928
DERMASON Extent -0.4094107 1.0849923 -0.3773397 0.7059211 -2.5359565 1.717135
DERMASON Solidity 1.9048820 2.5266305 0.7539219 0.4508961 -3.0472226 6.856987
DERMASON roundness 11.5719965 17.6951928 0.6539627 0.5131358 -23.1099440 46.253937
DERMASON Compactness -11.6261557 76.5612668 -0.1518543 0.8793019 -161.6834812 138.431170
DERMASON ShapeFactor1 32.8687823 83.4251381 0.3939913 0.6935874 -130.6414839 196.379049
DERMASON ShapeFactor2 9.9370278 126.0464884 0.0788362 0.9371629 -237.1095500 256.983606
DERMASON ShapeFactor3 -21.1220841 157.1726562 -0.1343878 0.8930959 -329.1748296 286.930661
DERMASON ShapeFactor4 1.8723203 5.9357876 0.3154291 0.7524359 -9.7616097 13.506250
HOROZ (Intercept) 9.6610647 22.7155730 0.4253058 0.6706138 -34.8606403 54.182770
HOROZ Area 22.2285014 200.3710110 0.1109367 0.9116665 -370.4914637 414.948466
HOROZ Perimeter 4.7474757 83.9478467 0.0565527 0.9549015 -159.7872805 169.282232
HOROZ MajorAxisLength 17.7453050 286.9688501 0.0618370 0.9506926 -544.7033058 580.193916
HOROZ MinorAxisLength -5.0289114 246.1323719 -0.0204317 0.9836990 -487.4394957 477.381673
HOROZ AspectRation -8.3300881 146.8478083 -0.0567260 0.9547635 -296.1465036 279.486328
HOROZ Eccentricity 12.3273490 214.8854858 0.0573671 0.9542528 -408.8404639 433.495162
HOROZ ConvexArea 19.7341600 229.8683754 0.0858498 0.9315858 -430.7995769 470.267897
HOROZ EquivDiameter 7.6098419 170.2963384 0.0446859 0.9643577 -326.1648480 341.384532
HOROZ Extent -0.1359260 0.8741651 -0.1554924 0.8764332 -1.8492581 1.577406
HOROZ Solidity 3.0692994 2.1397841 1.4343968 0.1514591 -1.1246004 7.263199
HOROZ roundness 1.5097606 12.7294359 0.1186039 0.9055892 -23.4394753 26.458997
HOROZ Compactness -2.2411137 220.0460161 -0.0101848 0.9918739 -433.5233802 429.041153
HOROZ ShapeFactor1 40.5371074 139.2427448 0.2911255 0.7709554 -232.3736575 313.447872
HOROZ ShapeFactor2 33.9740617 192.8097732 0.1762051 0.8601328 -343.9261496 411.874273
HOROZ ShapeFactor3 -8.3741346 193.5049042 -0.0432761 0.9654815 -387.6367778 370.888509
HOROZ ShapeFactor4 -4.1992209 8.1807257 -0.5133066 0.6077368 -20.2331487 11.834707
SEKER (Intercept) -7.8877652 47.3310220 -0.1666511 0.8676446 -100.6548637 84.879333
SEKER Area 6.3742694 138.3843182 0.0460621 0.9632608 -264.8540102 277.602549
SEKER Perimeter -5.4781496 216.0222854 -0.0253592 0.9797685 -428.8740488 417.917750
SEKER MajorAxisLength -0.8653203 200.3993814 -0.0043180 0.9965548 -393.6408903 391.910250
SEKER MinorAxisLength -5.1614017 305.1262614 -0.0169156 0.9865039 -603.1978848 592.875081
SEKER AspectRation 10.8541572 102.0768802 0.1063332 0.9153180 -189.2128517 210.921166
SEKER Eccentricity 5.9556281 85.4396859 0.0697056 0.9444280 -161.5030790 173.414335
SEKER ConvexArea 6.7719048 136.1817873 0.0497269 0.9603400 -260.1394937 273.683303
SEKER EquivDiameter -3.0943369 96.0564757 -0.0322137 0.9743016 -191.3615698 185.172896
SEKER Extent 0.6470415 1.3189784 0.4905626 0.6237358 -1.9381087 3.232192
SEKER Solidity 7.8427812 3.5255465 2.2245576 0.0261110 0.9328370 14.752725
SEKER roundness 4.8118331 19.7136601 0.2440862 0.8071640 -33.8262307 43.449897
SEKER Compactness -1.8052595 98.1954912 -0.0183843 0.9853322 -194.2648856 190.654367
SEKER ShapeFactor1 6.9470264 82.2987331 0.0844123 0.9327286 -154.3555263 168.249579
SEKER ShapeFactor2 33.3625077 132.5560443 0.2516861 0.8012837 -226.4425650 293.167580
SEKER ShapeFactor3 -1.7416148 122.0886703 -0.0142652 0.9886184 -241.0310115 237.547782
SEKER ShapeFactor4 1.3990297 6.8005195 0.2057239 0.8370066 -11.9297436 14.727803
SIRA (Intercept) -8.4667795 39.0099578 -0.2170415 0.8281760 -84.9248917 67.991333
SIRA Area 1.8622049 108.5209924 0.0171599 0.9863091 -210.8350318 214.559441
SIRA Perimeter -2.4601324 182.1650374 -0.0135050 0.9892249 -359.4970448 354.576780
SIRA MajorAxisLength -0.1270451 245.5910959 -0.0005173 0.9995873 -481.4767481 481.222658
SIRA MinorAxisLength -12.1784000 281.3636760 -0.0432835 0.9654756 -563.6410714 539.284271
SIRA AspectRation 8.9246871 88.6367320 0.1006884 0.9197979 -164.8001154 182.649489
SIRA Eccentricity 10.1628921 73.3498298 0.1385537 0.8898028 -133.6001325 153.925917
SIRA ConvexArea 2.7679511 101.1836917 0.0273557 0.9781760 -195.5484403 201.084343
SIRA EquivDiameter -7.7167344 80.2073221 -0.0962098 0.9233539 -164.9201970 149.486728
SIRA Extent 0.1179685 1.0177088 0.1159158 0.9077193 -1.8767041 2.112641
SIRA Solidity 2.5169753 2.3647400 1.0643772 0.2871579 -2.1178298 7.151781
SIRA roundness 10.3305977 19.0719956 0.5416632 0.5880506 -27.0498267 47.711022
SIRA Compactness 2.3836793 91.2461495 0.0261236 0.9791587 -176.4554876 181.222846
SIRA ShapeFactor1 13.7686117 89.7801845 0.1533591 0.8781151 -162.1973165 189.734540
SIRA ShapeFactor2 9.6705803 152.9188627 0.0632399 0.9495754 -290.0448831 309.386044
SIRA ShapeFactor3 9.1619888 159.4022048 0.0574772 0.9541651 -303.2605917 321.584569
SIRA ShapeFactor4 -2.7130070 5.5390267 -0.4897985 0.6242765 -13.5692998 8.143286

Output ini menunjukkan pengaruh tiap variabel terhadap peluang masuk ke suatu kelas. Nilai estimate positif meningkatkan peluang, negatif menurunkan, sedangkan p-value menunjukkan apakah pengaruhnya signifikan.Contoh pada kelas BOMBAY, Area (18.09) meningkatkan peluang, dan Eccentricity (-8.03) menurunkan, tetapi keduanya tidak signifikan karena p-value besar. Jadi, sebagian besar variabel tidak berpengaruh signifikan, sehingga model belum kuat dalam menjelaskan perbedaan kelas.

4. Relative Risk Ratio

exp(coef(fit_full))
##           (Intercept)         Area    Perimeter MajorAxisLength MinorAxisLength
## BOMBAY   2.301940e-02 7.245224e+07 1.124361e+04    5.846379e+05    2.791734e+01
## CALI     1.760641e-02 1.256633e-07 2.874816e+12    1.404099e-03    8.283007e+02
## DERMASON 3.182122e-05 2.912726e+05 3.085458e-03    1.298931e-01    4.758699e-03
## HOROZ    1.569449e+04 4.505215e+09 1.152929e+02    5.089651e+07    6.545933e-03
## SEKER    3.753074e-04 5.865567e+02 4.177052e-03    4.209167e-01    5.733657e-03
## SIRA     2.103412e-04 6.437916e+00 8.542364e-02    8.806939e-01    5.140295e-06
##          AspectRation Eccentricity   ConvexArea EquivDiameter     Extent
## BOMBAY   2.360799e+04 3.253841e-04 9.711866e+07  2.301145e+03 0.06259466
## CALI     2.607399e+01 7.210302e+00 2.941193e-02  1.270988e-01 1.72341194
## DERMASON 5.397355e-11 4.759934e-05 3.904552e+05  3.777286e-02 0.66404145
## HOROZ    2.411508e-04 2.257874e+05 3.719091e+08  2.017959e+03 0.87290724
## SEKER    5.174884e+04 3.859192e+02 8.729731e+02  4.530504e-02 1.90988205
## SIRA     7.515231e+03 2.592316e+04 1.592597e+01  4.453125e-04 1.12520869
##             Solidity    roundness  Compactness ShapeFactor1 ShapeFactor2
## BOMBAY     17.302285 2.307803e+04 1.421418e-01 5.529554e+11 7.381356e+10
## CALI       25.019751 1.499727e+03 8.285208e-01 9.416508e+00 1.150418e-01
## DERMASON    6.718615 1.060851e+05 8.929450e-06 1.882482e+14 2.068218e+04
## HOROZ      21.526815 4.525647e+00 1.063400e-01 4.027560e+17 5.685223e+14
## SEKER    2547.279440 1.229568e+02 1.644318e-01 1.040052e+03 3.084274e+14
## SIRA       12.391061 3.065643e+04 1.084473e+01 9.541839e+05 1.584454e+04
##          ShapeFactor3 ShapeFactor4
## BOMBAY   1.895500e+00   0.01581713
## CALI     2.970573e-02   0.01090310
## DERMASON 6.711127e-10   6.50336861
## HOROZ    2.307595e-04   0.01500726
## SEKER    1.752372e-01   4.05126710
## SIRA     9.527988e+03   0.06633703
tidy(fit_full, conf.int = TRUE, exponentiate = TRUE) %>%
  kable() %>%
  kable_styling("basic", full_width = FALSE)
y.level term estimate std.error statistic p.value conf.low conf.high
BOMBAY (Intercept) 2.301940e-02 201.4044645 -0.0187256 0.9850600 0.0000000 6.278920e+169
BOMBAY Area 7.245224e+07 111.6362264 0.1621198 0.8712115 0.0000000 7.673262e+102
BOMBAY Perimeter 1.124361e+04 35.7928834 0.2605980 0.7944025 0.0000000 3.295060e+34
BOMBAY MajorAxisLength 5.846379e+05 62.9607994 0.2109050 0.8329614 0.0000000 2.286739e+59
BOMBAY MinorAxisLength 2.791734e+01 129.6399125 0.0256807 0.9795120 0.0000000 6.245507e+111
BOMBAY AspectRation 2.360799e+04 189.2732648 0.0532000 0.9575725 0.0000000 3.039163e+165
BOMBAY Eccentricity 3.254000e-04 259.7124767 -0.0309207 0.9753327 0.0000000 3.802396e+217
BOMBAY ConvexArea 9.711866e+07 130.0981447 0.1413659 0.8875809 0.0000000 5.333893e+118
BOMBAY EquivDiameter 2.301145e+03 84.5707289 0.0915348 0.9270677 0.0000000 2.231921e+75
BOMBAY Extent 6.259470e-02 29.9089350 -0.0926504 0.9261813 0.0000000 1.799156e+24
BOMBAY Solidity 1.730228e+01 33.0875041 0.0861606 0.9313388 0.0000000 2.524864e+29
BOMBAY roundness 2.307803e+04 180.2942967 0.0557235 0.9555620 0.0000000 6.760555e+157
BOMBAY Compactness 1.421418e-01 78.7171191 -0.0247841 0.9802272 0.0000000 1.435011e+66
BOMBAY ShapeFactor1 5.529554e+11 108.4525683 0.2493122 0.8031193 0.0000000 1.142046e+104
BOMBAY ShapeFactor2 7.381356e+10 123.4400233 0.2027285 0.8393473 0.0000000 8.719157e+115
BOMBAY ShapeFactor3 1.895500e+00 79.8091723 0.0080126 0.9936069 0.0000000 1.627100e+68
BOMBAY ShapeFactor4 1.581710e-02 49.7910172 -0.0832813 0.9336279 0.0000000 3.813453e+40
CALI (Intercept) 1.760640e-02 12.3883031 -0.3260731 0.7443691 0.0000000 6.174666e+08
CALI Area 1.000000e-07 278.2132912 -0.0571132 0.9544550 0.0000000 8.218476e+229
CALI Perimeter 2.874816e+12 104.9340232 0.2733814 0.7845601 0.0000000 6.006376e+101
CALI MajorAxisLength 1.404100e-03 237.0405191 -0.0277099 0.9778936 0.0000000 8.253788e+198
CALI MinorAxisLength 8.283007e+02 235.3735334 0.0285477 0.9772253 0.0000000 1.855679e+203
CALI AspectRation 2.607399e+01 105.8143875 0.0308175 0.9754151 0.0000000 3.058985e+91
CALI Eccentricity 7.210302e+00 83.1869779 0.0237478 0.9810537 0.0000000 4.643414e+71
CALI ConvexArea 2.941190e-02 253.3889609 -0.0139168 0.9888964 0.0000000 1.424289e+214
CALI EquivDiameter 1.270988e-01 164.1089122 -0.0125696 0.9899711 0.0000000 6.221581e+138
CALI Extent 1.723412e+00 0.5964644 0.9125541 0.3614771 0.5353992 5.547541e+00
CALI Solidity 2.501975e+01 2.5265594 1.2743281 0.2025472 0.1768771 3.539111e+03
CALI roundness 1.499727e+03 14.3179777 0.5107592 0.6095197 0.0000000 2.309389e+15
CALI Compactness 8.285208e-01 272.6617748 -0.0006899 0.9994495 0.0000000 1.019593e+232
CALI ShapeFactor1 9.416508e+00 134.7612185 0.0166403 0.9867236 0.0000000 4.817781e+115
CALI ShapeFactor2 1.150418e-01 150.8039657 -0.0143395 0.9885591 0.0000000 2.663323e+127
CALI ShapeFactor3 2.970570e-02 234.3129457 -0.0150073 0.9880263 0.0000000 8.324941e+197
CALI ShapeFactor4 1.090310e-02 5.8535055 -0.7719662 0.4401345 0.0000001 1.047280e+03
DERMASON (Intercept) 3.180000e-05 47.2274958 -0.2192659 0.8264430 0.0000000 5.044686e+35
DERMASON Area 2.912726e+05 110.4267818 0.1139399 0.9092854 0.0000000 2.882350e+99
DERMASON Perimeter 3.085500e-03 197.7383223 -0.0292359 0.9766765 0.0000000 6.375067e+165
DERMASON MajorAxisLength 1.298931e-01 261.9917440 -0.0077905 0.9937842 0.0000000 1.322401e+222
DERMASON MinorAxisLength 4.758700e-03 324.2844503 -0.0164910 0.9868427 0.0000000 5.115791e+273
DERMASON AspectRation 0.000000e+00 104.8349324 -0.2255215 0.8215736 0.0000000 9.286184e+78
DERMASON Eccentricity 4.760000e-05 84.6967995 -0.1175097 0.9064562 0.0000000 5.910816e+67
DERMASON ConvexArea 3.904552e+05 107.3851748 0.1198961 0.9045654 0.0000000 9.954003e+96
DERMASON EquivDiameter 3.777290e-02 49.5443247 -0.0661259 0.9472776 0.0000000 5.615462e+40
DERMASON Extent 6.640415e-01 1.0849923 -0.3773397 0.7059211 0.0791859 5.568552e+00
DERMASON Solidity 6.718615e+00 2.5266305 0.7539219 0.4508961 0.0474906 9.504986e+02
DERMASON roundness 1.060851e+05 17.6951928 0.6539627 0.5131358 0.0000000 1.224136e+20
DERMASON Compactness 8.900000e-06 76.5612668 -0.1518543 0.8793019 0.0000000 1.317932e+60
DERMASON ShapeFactor1 1.882482e+14 83.4251381 0.3939913 0.6935874 0.0000000 1.933469e+85
DERMASON ShapeFactor2 2.068218e+04 126.0464884 0.0788362 0.9371629 0.0000000 4.041679e+111
DERMASON ShapeFactor3 0.000000e+00 157.1726562 -0.1343878 0.8930959 0.0000000 4.096406e+124
DERMASON ShapeFactor4 6.503369e+00 5.9357876 0.3154291 0.7524359 0.0000576 7.339897e+05
HOROZ (Intercept) 1.569449e+04 22.7155730 0.4253058 0.6706138 0.0000000 3.398427e+23
HOROZ Area 4.505215e+09 200.3710110 0.1109367 0.9116665 0.0000000 1.621173e+180
HOROZ Perimeter 1.152929e+02 83.9478467 0.0565527 0.9549015 0.0000000 3.298672e+73
HOROZ MajorAxisLength 5.089651e+07 286.9688501 0.0618370 0.9506926 0.0000000 9.440958e+251
HOROZ MinorAxisLength 6.545900e-03 246.1323719 -0.0204317 0.9836990 0.0000000 2.109727e+207
HOROZ AspectRation 2.412000e-04 146.8478083 -0.0567260 0.9547635 0.0000000 2.395354e+121
HOROZ Eccentricity 2.257874e+05 214.8854858 0.0573671 0.9542528 0.0000000 1.838894e+188
HOROZ ConvexArea 3.719091e+08 229.8683754 0.0858498 0.9315858 0.0000000 1.716930e+204
HOROZ EquivDiameter 2.017959e+03 170.2963384 0.0446859 0.9643577 0.0000000 1.825654e+148
HOROZ Extent 8.729072e-01 0.8741651 -0.1554924 0.8764332 0.1573539 4.842379e+00
HOROZ Solidity 2.152682e+01 2.1397841 1.4343968 0.1514591 0.3247822 1.426814e+03
HOROZ roundness 4.525647e+00 12.7294359 0.1186039 0.9055892 0.0000000 3.097392e+11
HOROZ Compactness 1.063400e-01 220.0460161 -0.0101848 0.9918739 0.0000000 2.138972e+186
HOROZ ShapeFactor1 4.027560e+17 139.2427448 0.2911255 0.7709554 0.0000000 1.344873e+136
HOROZ ShapeFactor2 5.685223e+14 192.8097732 0.1762051 0.8601328 0.0000000 7.494178e+178
HOROZ ShapeFactor3 2.308000e-04 193.5049042 -0.0432761 0.9654815 0.0000000 1.188044e+161
HOROZ ShapeFactor4 1.500730e-02 8.1807257 -0.5133066 0.6077368 0.0000000 1.379583e+05
SEKER (Intercept) 3.753000e-04 47.3310220 -0.1666511 0.8676446 0.0000000 7.288298e+36
SEKER Area 5.865567e+02 138.3843182 0.0460621 0.9632608 0.0000000 3.641289e+120
SEKER Perimeter 4.177100e-03 216.0222854 -0.0253592 0.9797685 0.0000000 3.157712e+181
SEKER MajorAxisLength 4.209167e-01 200.3993814 -0.0043180 0.9965548 0.0000000 1.601249e+170
SEKER MinorAxisLength 5.733700e-03 305.1262614 -0.0169156 0.9865039 0.0000000 3.036521e+257
SEKER AspectRation 5.174884e+04 102.0768802 0.1063332 0.9153180 0.0000000 3.998514e+91
SEKER Eccentricity 3.859192e+02 85.4396859 0.0697056 0.9444280 0.0000000 2.055365e+75
SEKER ConvexArea 8.729731e+02 136.1817873 0.0497269 0.9603400 0.0000000 7.230168e+118
SEKER EquivDiameter 4.530500e-02 96.0564757 -0.0322137 0.9743016 0.0000000 2.627646e+80
SEKER Extent 1.909882e+00 1.3189784 0.4905626 0.6237358 0.1439760 2.533512e+01
SEKER Solidity 2.547279e+03 3.5255465 2.2245576 0.0261110 2.5417098 2.552861e+06
SEKER roundness 1.229568e+02 19.7136601 0.2440862 0.8071640 0.0000000 7.413964e+18
SEKER Compactness 1.644318e-01 98.1954912 -0.0183843 0.9853322 0.0000000 6.311599e+82
SEKER ShapeFactor1 1.040052e+03 82.2987331 0.0844123 0.9327286 0.0000000 1.174529e+73
SEKER ShapeFactor2 3.084274e+14 132.5560443 0.2516861 0.8012837 0.0000000 2.094414e+127
SEKER ShapeFactor3 1.752372e-01 122.0886703 -0.0142652 0.9886184 0.0000000 1.464505e+103
SEKER ShapeFactor4 4.051267e+00 6.8005195 0.2057239 0.8370066 0.0000066 2.490024e+06
SIRA (Intercept) 2.103000e-04 39.0099578 -0.2170415 0.8281760 0.0000000 3.374898e+29
SIRA Area 6.437916e+00 108.5209924 0.0171599 0.9863091 0.0000000 1.520483e+93
SIRA Perimeter 8.542360e-02 182.1650374 -0.0135050 0.9892249 0.0000000 9.789015e+153
SIRA MajorAxisLength 8.806939e-01 245.5910959 -0.0005173 0.9995873 0.0000000 9.825278e+208
SIRA MinorAxisLength 5.100000e-06 281.3636760 -0.0432835 0.9654756 0.0000000 1.615040e+234
SIRA AspectRation 7.515231e+03 88.6367320 0.1006884 0.9197979 0.0000000 2.107004e+79
SIRA Eccentricity 2.592316e+04 73.3498298 0.1385537 0.8898028 0.0000000 7.066042e+66
SIRA ConvexArea 1.592597e+01 101.1836917 0.0273557 0.9781760 0.0000000 2.137078e+87
SIRA EquivDiameter 4.453000e-04 80.2073221 -0.0962098 0.9233539 0.0000000 8.341827e+64
SIRA Extent 1.125209e+00 1.0177088 0.1159158 0.9077193 0.1530939 8.270055e+00
SIRA Solidity 1.239106e+01 2.3647400 1.0643772 0.2871579 0.1202924 1.276377e+03
SIRA roundness 3.065643e+04 19.0719956 0.5416632 0.5880506 0.0000000 5.255737e+20
SIRA Compactness 1.084473e+01 91.2461495 0.0261236 0.9791587 0.0000000 5.059202e+78
SIRA ShapeFactor1 9.541839e+05 89.7801845 0.1533591 0.8781151 0.0000000 2.515728e+82
SIRA ShapeFactor2 1.584454e+04 152.9188627 0.0632399 0.9495754 0.0000000 2.315536e+134
SIRA ShapeFactor3 9.527988e+03 159.4022048 0.0574772 0.9541651 0.0000000 4.596253e+139
SIRA ShapeFactor4 6.633700e-02 5.5390267 -0.4897985 0.6242765 0.0000013 3.440203e+03

Output ini adalah odds ratio (exp(coef)), yang menunjukkan perubahan peluang tiap kelas. Nilai > 1 berarti meningkatkan peluang, < 1 menurunkan, dan p-value menentukan signifikansi. Contoh, pada BOMBAY, Area (7.24e+07) meningkatkan peluang dan Eccentricity (3.25e-04) menurunkan, tetapi tidak signifikan. Pada SEKER, Solidity (2547) signifikan (p < 0.05), sehingga benar-benar meningkatkan peluang. Jadi, sebagian besar variabel tidak signifikan, hanya sedikit yang benar-benar berpengaruh.

5. Marginal Effect (area)

mfx_selected <- avg_comparisons(
  fit_full,
  variables = c("Area", "Perimeter", "MajorAxisLength"),
  type = "probs"
)
mfx_selected
## 
##             Term    Group  Estimate Std. Error         z Pr(>|z|)      S
##  Area            BARBUNYA -0.085192    1.35258  -0.06299    0.950    0.1
##  Area            BOMBAY    0.004596    0.36184   0.01270    0.990    0.0
##  Area            CALI     -0.142745    0.00383 -37.24983   <0.001 1006.5
##  Area            DERMASON  0.083311    4.95192   0.01682    0.987    0.0
##  Area            HOROZ     0.346089    4.64336   0.07453    0.941    0.1
##  Area            SEKER    -0.063264    3.17938  -0.01990    0.984    0.0
##  Area            SIRA     -0.142795    0.00726 -19.66228   <0.001  283.5
##  MajorAxisLength BARBUNYA -0.054277    1.96395  -0.02764    0.978    0.0
##  MajorAxisLength BOMBAY    0.006020    0.33197   0.01813    0.986    0.0
##  MajorAxisLength CALI     -0.142712    0.01145 -12.46878   <0.001  116.1
##  MajorAxisLength DERMASON -0.120942    3.68719  -0.03280    0.974    0.0
##  MajorAxisLength HOROZ     0.442883    5.98813   0.07396    0.941    0.1
##  MajorAxisLength SEKER    -0.007279    1.71083  -0.00425    0.997    0.0
##  MajorAxisLength SIRA     -0.123691    3.26825  -0.03785    0.970    0.0
##  Perimeter       BARBUNYA -0.142911    0.00522 -27.39630   <0.001  546.5
##  Perimeter       BOMBAY   -0.000752    0.30525  -0.00246    0.998    0.0
##  Perimeter       CALI      0.424362    1.32340   0.32066    0.748    0.4
##  Perimeter       DERMASON -0.062407    3.78881  -0.01647    0.987    0.0
##  Perimeter       HOROZ    -0.101781    1.48150  -0.06870    0.945    0.1
##  Perimeter       SEKER    -0.035249    2.43800  -0.01446    0.988    0.0
##  Perimeter       SIRA     -0.081262    4.76835  -0.01704    0.986    0.0
##    2.5 % 97.5 %
##   -2.736  2.566
##   -0.705  0.714
##   -0.150 -0.135
##   -9.622  9.789
##   -8.755  9.447
##   -6.295  6.168
##   -0.157 -0.129
##   -3.904  3.795
##   -0.645  0.657
##   -0.165 -0.120
##   -7.348  7.106
##  -11.294 12.179
##   -3.360  3.346
##   -6.529  6.282
##   -0.153 -0.133
##   -0.599  0.598
##   -2.169  3.018
##   -7.488  7.364
##   -3.005  2.802
##   -4.814  4.743
##   -9.427  9.265
## 
## Type: probs
## Comparison: +1

Output ini menunjukkan marginal effect, yaitu perubahan probabilitas kelas saat variabel naik 1 satuan. Nilai positif berarti peluang naik, negatif berarti turun. Contoh, Area meningkatkan peluang HOROZ (0.346) tapi menurunkan CALI (-0.142). MajorAxisLength juga menaikkan HOROZ (0.442), sedangkan Perimeter menaikkan CALI (0.424). Jadi, tiap variabel memberi pengaruh berbeda pada tiap kelas, dan marginal effect menunjukkan dampaknya secara langsung pada probabilitas.

Evaluasi Model

# prediksi
pred <- predict(fit_full, newdata = testData)

# confusion matrix
conf_matrix <- confusionMatrix(pred, testData$Class)
print(conf_matrix)
## Confusion Matrix and Statistics
## 
##           Reference
## Prediction BARBUNYA BOMBAY CALI DERMASON HOROZ SEKER SIRA
##   BARBUNYA       21      0    2        0     1     0    0
##   BOMBAY          0     26    0        0     0     0    0
##   CALI            4      0   24        0     1     0    0
##   DERMASON        0      0    0       21     0     1    2
##   HOROZ           0      0    0        0    24     0    1
##   SEKER           0      0    0        0     0    24    1
##   SIRA            1      0    0        5     0     1   22
## 
## Overall Statistics
##                                           
##                Accuracy : 0.8901          
##                  95% CI : (0.8354, 0.9316)
##     No Information Rate : 0.1429          
##     P-Value [Acc > NIR] : < 2.2e-16       
##                                           
##                   Kappa : 0.8718          
##                                           
##  Mcnemar's Test P-Value : NA              
## 
## Statistics by Class:
## 
##                      Class: BARBUNYA Class: BOMBAY Class: CALI Class: DERMASON
## Sensitivity                   0.8077        1.0000      0.9231          0.8077
## Specificity                   0.9808        1.0000      0.9679          0.9808
## Pos Pred Value                0.8750        1.0000      0.8276          0.8750
## Neg Pred Value                0.9684        1.0000      0.9869          0.9684
## Prevalence                    0.1429        0.1429      0.1429          0.1429
## Detection Rate                0.1154        0.1429      0.1319          0.1154
## Detection Prevalence          0.1319        0.1429      0.1593          0.1319
## Balanced Accuracy             0.8942        1.0000      0.9455          0.8942
##                      Class: HOROZ Class: SEKER Class: SIRA
## Sensitivity                0.9231       0.9231      0.8462
## Specificity                0.9936       0.9936      0.9551
## Pos Pred Value             0.9600       0.9600      0.7586
## Neg Pred Value             0.9873       0.9873      0.9739
## Prevalence                 0.1429       0.1429      0.1429
## Detection Rate             0.1319       0.1319      0.1209
## Detection Prevalence       0.1374       0.1374      0.1593
## Balanced Accuracy          0.9583       0.9583      0.9006
# akurasi
accuracy <- conf_matrix$overall["Accuracy"]
print(accuracy)
##  Accuracy 
## 0.8901099

Code ini digunakan untuk mengevaluasi performa model klasifikasi multinomial. Pertama, model digunakan untuk memprediksi kelas data uji (testData) menggunakan predict. Hasil prediksi kemudian dibandingkan dengan label asli menggunakan confusion matrix, yang menunjukkan jumlah prediksi benar dan salah untuk setiap kelas.

Dari confusion matrix terlihat bahwa sebagian besar data berhasil diklasifikasikan dengan benar (nilai diagonal tinggi), meskipun masih ada beberapa kesalahan, misalnya kelas CALI kadang diprediksi sebagai BARBUNYA, dan SIRA sering tertukar dengan DERMASON. Nilai akurasi sebesar 0.8901 (89%) menunjukkan bahwa model mampu mengklasifikasikan data dengan cukup baik. Selain itu, nilai Kappa = 0.8718 menandakan kesesuaian prediksi dengan data asli sangat kuat. Beberapa kelas seperti BOMBAY memiliki performa sempurna (sensitivity dan specificity = 1), sedangkan kelas seperti SIRA memiliki performa sedikit lebih rendah karena masih ada kesalahan prediksi.

Secara keseluruhan, model sudah bekerja dengan baik dan cukup akurat, meskipun masih ada sedikit kebingungan antar beberapa kelas yang memiliki karakteristik mirip.