Oke, sekarang kita akan membahas tentang Ruang Vektor (Vector Spaces)

Sebuah ruang vektor adalah dasar dalam banyak bidang. Sebagai contoh, dalam statistik, kita mengasumsikan properti dari ruang vektor agar dapat melakukan analisis statistik pada kumpulan data. Pada bab ini, kita fokus pada ruang vektor dan properti dasarnya. Pertama, kita mendefinisikan ruang vektor dan kemudian untuk aplikasinya, kita mengasumsikan “ruang Euklides” sebagai ruang vektor.

Contoh Pengantar Data Science

Dalam ilmu data, terdapat tiga sub-area dasar dari model statistik: pembelajaran terawasi (supervised learning), pembelajaran tak terawasi (unsupervised learning), dan pembelajaran penguatan (reinforcement learning). Pada bab ini, kita fokus pada pembelajaran tak terawasi, terutama klasterisasi. Model pembelajaran tak terawasi adalah metode statistik deskriptif, berbeda dengan pembelajaran terawasi yang merupakan metode statistik inferensial untuk memprediksi hasil atau parameter berdasarkan dataset. Salah satu area utama dalam pembelajaran tak terawasi adalah klasterisasi. Metode klasterisasi digunakan untuk mengelompokkan observasi dalam dataset berdasarkan “kemiripan” mereka. Pengukuran “kemiripan” ini didefinisikan sebagai “produk dot” vektor dalam ruang vektor.

Dalam bagian ini, kita akan mempertimbangkan dataset kejahatan dari Amerika Serikat, yaitu dataset “USArrests” dari R. Data ini berisi informasi tentang penangkapan yang dilakukan di Amerika Serikat, yaitu jumlah penangkapan rata-rata per 100.000 penduduk untuk kasus serangan, pembunuhan, pemerkosaan, dan persentase populasi yang tinggal di daerah perkotaan di masing-masing dari 50 negara bagian pada tahun 1973.

Di sini, kita akan menggunakan fungsi hclust() dari R untuk melihat pengelompokan (klasterisasi), yaitu mengelompokkan berdasarkan kemiripan antara setiap observasi. Pertama, kita akan mengunggah data “USArrests” dari R.

df <-USArrests

Kita dapat melihat 6 observasi pertama dengan menggunakan fungsi head() seperti berikut:

head(df)
##            Murder Assault UrbanPop Rape
## Alabama      13.2     236       58 21.2
## Alaska       10.0     263       48 44.5
## Arizona       8.1     294       80 31.0
## Arkansas      8.8     190       50 19.5
## California    9.0     276       91 40.6
## Colorado      7.9     204       78 38.7

Kemudian kita membersihkan data dengan menghapus nilai-nilai yang hilang menggunakan fungsi na.omit().

df <-na.omit(df)
df
##                Murder Assault UrbanPop Rape
## Alabama          13.2     236       58 21.2
## Alaska           10.0     263       48 44.5
## Arizona           8.1     294       80 31.0
## Arkansas          8.8     190       50 19.5
## California        9.0     276       91 40.6
## Colorado          7.9     204       78 38.7
## Connecticut       3.3     110       77 11.1
## Delaware          5.9     238       72 15.8
## Florida          15.4     335       80 31.9
## Georgia          17.4     211       60 25.8
## Hawaii            5.3      46       83 20.2
## Idaho             2.6     120       54 14.2
## Illinois         10.4     249       83 24.0
## Indiana           7.2     113       65 21.0
## Iowa              2.2      56       57 11.3
## Kansas            6.0     115       66 18.0
## Kentucky          9.7     109       52 16.3
## Louisiana        15.4     249       66 22.2
## Maine             2.1      83       51  7.8
## Maryland         11.3     300       67 27.8
## Massachusetts     4.4     149       85 16.3
## Michigan         12.1     255       74 35.1
## Minnesota         2.7      72       66 14.9
## Mississippi      16.1     259       44 17.1
## Missouri          9.0     178       70 28.2
## Montana           6.0     109       53 16.4
## Nebraska          4.3     102       62 16.5
## Nevada           12.2     252       81 46.0
## New Hampshire     2.1      57       56  9.5
## New Jersey        7.4     159       89 18.8
## New Mexico       11.4     285       70 32.1
## New York         11.1     254       86 26.1
## North Carolina   13.0     337       45 16.1
## North Dakota      0.8      45       44  7.3
## Ohio              7.3     120       75 21.4
## Oklahoma          6.6     151       68 20.0
## Oregon            4.9     159       67 29.3
## Pennsylvania      6.3     106       72 14.9
## Rhode Island      3.4     174       87  8.3
## South Carolina   14.4     279       48 22.5
## South Dakota      3.8      86       45 12.8
## Tennessee        13.2     188       59 26.9
## Texas            12.7     201       80 25.5
## Utah              3.2     120       80 22.9
## Vermont           2.2      48       32 11.2
## Virginia          8.5     156       63 20.7
## Washington        4.0     145       73 26.2
## West Virginia     5.7      81       39  9.3
## Wisconsin         2.6      53       66 10.8
## Wyoming           6.8     161       60 15.6

Kemudian kita menggunakan fungsi scale() untuk “standarisasi” setiap pengukuran. Alasan mengapa kita menerapkan fungsi ini adalah karena beberapa pengukuran memiliki nilai yang jauh lebih besar daripada yang lain. Misalnya, seorang siswa mengambil tes ACT dan SAT. Skor SAT memiliki skor maksimum 1600 sedangkan ACT memiliki skor maksimum 36. Jika siswa ini ingin tahu tes mana di mana dia atau dia lebih baik, kita tidak bisa hanya membandingkan skor-skornya. Jika kita menghitung seberapa jauh skor siswa untuk SAT atau ACT dari rerata, maka kita dapat membandingkan skor siswa pada ACT dan SAT. Fungsi scale() menghitung seberapa jauh setiap observasi dari rerata.

df <-scale(df)
df
##                     Murder     Assault    UrbanPop         Rape
## Alabama         1.24256408  0.78283935 -0.52090661 -0.003416473
## Alaska          0.50786248  1.10682252 -1.21176419  2.484202941
## Arizona         0.07163341  1.47880321  0.99898006  1.042878388
## Arkansas        0.23234938  0.23086801 -1.07359268 -0.184916602
## California      0.27826823  1.26281442  1.75892340  2.067820292
## Colorado        0.02571456  0.39885929  0.86080854  1.864967207
## Connecticut    -1.03041900 -0.72908214  0.79172279 -1.081740768
## Delaware       -0.43347395  0.80683810  0.44629400 -0.579946294
## Florida         1.74767144  1.97077766  0.99898006  1.138966691
## Georgia         2.20685994  0.48285493 -0.38273510  0.487701523
## Hawaii         -0.57123050 -1.49704226  1.20623733 -0.110181255
## Idaho          -1.19113497 -0.60908837 -0.79724965 -0.750769945
## Illinois        0.59970018  0.93883125  1.20623733  0.295524916
## Indiana        -0.13500142 -0.69308401 -0.03730631 -0.024769429
## Iowa           -1.28297267 -1.37704849 -0.58999237 -1.060387812
## Kansas         -0.41051452 -0.66908525  0.03177945 -0.345063775
## Kentucky        0.43898421 -0.74108152 -0.93542116 -0.526563903
## Louisiana       1.74767144  0.93883125  0.03177945  0.103348309
## Maine          -1.30593210 -1.05306531 -1.00450692 -1.434064548
## Maryland        0.80633501  1.55079947  0.10086521  0.701231086
## Massachusetts  -0.77786532 -0.26110644  1.34440885 -0.526563903
## Michigan        0.99001041  1.01082751  0.58446551  1.480613993
## Minnesota      -1.16817555 -1.18505846  0.03177945 -0.676034598
## Mississippi     1.90838741  1.05882502 -1.48810723 -0.441152078
## Missouri        0.27826823  0.08687549  0.30812248  0.743936999
## Montana        -0.41051452 -0.74108152 -0.86633540 -0.515887425
## Nebraska       -0.80082475 -0.82507715 -0.24456358 -0.505210947
## Nevada          1.01296983  0.97482938  1.06806582  2.644350114
## New Hampshire  -1.30593210 -1.36504911 -0.65907813 -1.252564419
## New Jersey     -0.08908257 -0.14111267  1.62075188 -0.259651949
## New Mexico      0.82929443  1.37080881  0.30812248  1.160319648
## New York        0.76041616  0.99882813  1.41349461  0.519730957
## North Carolina  1.19664523  1.99477641 -1.41902147 -0.547916860
## North Dakota   -1.60440462 -1.50904164 -1.48810723 -1.487446939
## Ohio           -0.11204199 -0.60908837  0.65355127  0.017936483
## Oklahoma       -0.27275797 -0.23710769  0.16995096 -0.131534211
## Oregon         -0.66306820 -0.14111267  0.10086521  0.861378259
## Pennsylvania   -0.34163624 -0.77707965  0.44629400 -0.676034598
## Rhode Island   -1.00745957  0.03887798  1.48258036 -1.380682157
## South Carolina  1.51807718  1.29881255 -1.21176419  0.135377743
## South Dakota   -0.91562187 -1.01706718 -1.41902147 -0.900240639
## Tennessee       1.24256408  0.20686926 -0.45182086  0.605142783
## Texas           1.12776696  0.36286116  0.99898006  0.455672088
## Utah           -1.05337842 -0.60908837  0.99898006  0.178083656
## Vermont        -1.28297267 -1.47304350 -2.31713632 -1.071064290
## Virginia        0.16347111 -0.17711080 -0.17547783 -0.056798864
## Washington     -0.86970302 -0.30910395  0.51537975  0.530407436
## West Virginia  -0.47939280 -1.07706407 -1.83353601 -1.273917376
## Wisconsin      -1.19113497 -1.41304662  0.03177945 -1.113770203
## Wyoming        -0.22683912 -0.11711392 -0.38273510 -0.601299251
## attr(,"scaled:center")
##   Murder  Assault UrbanPop     Rape 
##    7.788  170.760   65.540   21.232 
## attr(,"scaled:scale")
##    Murder   Assault  UrbanPop      Rape 
##  4.355510 83.337661 14.474763  9.366385

Kemudian kita menggunakan “jarak Euclidean” sebagai pengukuran seberapa jauh dua observasi berbeda satu sama lain. Di sini, “jarak Euclidean” adalah akar kuadrat dari produk dalam (inner product) dari dua vektor dalam R4 untuk data “USArrests” (kita akan membahas produk dalam dalam Bab 5). Kita menyimpan jarak antara setiap pasangan observasi dalam data “USArrests” dalam bentuk matriks 50x50 menggunakan fungsi dist().

d <-dist(df,method="euclidean")
d
##                  Alabama    Alaska   Arizona  Arkansas California  Colorado
## Alaska         2.7037541                                                   
## Arizona        2.2935197 2.7006429                                         
## Arkansas       1.2898102 2.8260386 2.7177583                               
## California     3.2631104 3.0125415 1.3104842 3.7636409                     
## Colorado       2.6510673 2.3265187 1.3650307 2.8310512  1.2876185          
## Connecticut    3.2152975 4.7399125 3.2628575 2.6076395  4.0663898 3.3279920
## Delaware       2.0192927 3.6213633 1.9093696 1.8003239  3.0737852 2.5547456
## Florida        2.2981353 2.9967642 1.7493928 3.3721968  2.0250039 2.4458600
## Georgia        1.1314351 2.8194388 2.7871963 2.2117614  3.3780585 2.8649105
## Hawaii         3.3885300 4.5301340 3.2621208 2.9723097  3.6589083 2.8233524
## Idaho          2.9146623 4.0580555 3.5210071 1.7687255  4.4879436 3.4767685
## Illinois       1.8734993 3.2670626 1.0825512 2.4626424  1.9117469 1.7898322
## Indiana        2.0761411 3.3655952 2.6407486 1.4450503  3.4061273 2.3655622
## Iowa           3.4878952 4.7251910 4.1157513 2.4252661  4.9708591 3.9406898
## Kansas         2.2941096 3.6808173 2.7762838 1.5718411  3.6071725 2.6272281
## Kentucky       1.8475879 3.5440903 3.3567681 1.0598104  4.2463809 3.2274013
## Louisiana      0.7722224 2.9631431 2.2178519 2.0254276  3.0176625 2.6546743
## Maine          3.4851115 4.8322605 4.2961903 2.3621893  5.2699843 4.2713441
## Maryland       1.2896460 2.2777590 1.2117356 2.0582244  2.2312581 1.9667562
## Massachusetts  2.9874810 4.3729925 2.5162281 2.6881270  3.2156499 2.6522793
## Michigan       1.8814771 2.1154937 1.1940906 2.5895050  1.5146739 1.2363108
## Minnesota      3.2314338 4.4266606 3.5388450 2.3300992  4.3123134 3.3283853
## Mississippi    1.2831907 3.2554326 3.4551406 1.9318631  4.4200736 3.8491042
## Missouri       1.6309686 2.5360573 1.5958731 1.6717500  2.2891751 1.3127406
## Montana        2.3317271 3.6575988 3.3270869 1.2290066  4.2494176 3.1845338
## Nebraska       2.6625170 3.9136902 3.1641791 1.7240495  4.0197242 3.0034613
## Nevada         3.1024305 2.3443182 1.9260292 3.7086787  1.1968261 1.3988595
## New Hampshire  3.5619825 4.8650686 4.2430411 2.4949861  5.1270892 4.1126287
## New Jersey     2.6980230 4.1791832 2.1755787 2.7398478  2.7463023 2.3229870
## New Mexico     1.5993970 2.0580889 1.0376848 2.3183196  1.8010201 1.5467439
## New York       2.0723680 3.2903769 1.0725219 2.7478626  1.6787069 1.7363385
## North Carolina 1.6043662 3.2403071 3.1478947 2.0717938  4.2802569 3.8649275
## North Dakota   4.0614988 5.2110254 4.9319844 2.8756492  5.8660699 4.8014019
## Ohio           2.2698519 3.5903348 2.3585705 1.9617104  3.0133425 2.1188236
## Oklahoma       1.9570874 3.3416664 2.2648377 1.4224574  3.1488712 2.2263966
## Oregon         2.3705678 2.6990696 2.0008664 1.8477626  2.6574019 1.5331980
## Pennsylvania   2.5161340 4.1239537 2.9188907 1.9739986  3.7144562 2.8541709
## Rhode Island   3.3951297 5.0629572 3.0570151 3.0883430  3.8883995 3.4810739
## South Carolina 0.9157968 2.5640542 2.7992041 1.7074195  3.7546959 3.2131137
## South Dakota   3.0835587 4.2467198 4.1020099 1.8724822  5.0529153 3.9667318
## Tennessee      0.8407489 2.3362541 2.2989846 1.4254486  3.0119267 2.1972111
## Texas          1.6463225 3.1527905 1.6448574 2.3505545  2.1698156 1.7947199
## Utah           3.0906007 3.9480881 2.5244431 2.6049855  3.0701663 2.2461228
## Vermont        3.9791527 4.8707876 5.1003665 2.7442984  6.0323504 4.8924735
## Virginia       1.4859733 3.0492081 2.3106550 0.9971035  3.2159723 2.2622539
## Washington     2.6481824 3.2715253 2.1399117 2.1313402  2.7746720 1.7897920
## West Virginia  3.1243471 4.5004558 4.4974190 1.9951691  5.4883565 4.4210375
## Wisconsin      3.5047330 4.8711543 3.9425867 2.6102451  4.7354960 3.7846917
## Wyoming        1.8291027 3.4993456 2.6923028 0.9912639  3.7242766 2.8211492
##                Connecticut  Delaware   Florida   Georgia    Hawaii     Idaho
## Alaska                                                                      
## Arizona                                                                     
## Arkansas                                                                    
## California                                                                  
## Colorado                                                                    
## Connecticut                                                                 
## Delaware         1.7568475                                                  
## Florida          4.4700701 3.0614170                                        
## Georgia          3.9738227 2.9838715 2.1812958                              
## Hawaii           1.3843291 2.4748807 4.3596338 3.8105218                    
## Idaho            1.6354214 2.0382540 4.6999827 3.8005715 2.3658101          
## Illinois         2.7400560 1.5584719 1.7711863 2.3135778 2.7329756 3.2728945
## Indiana          1.6147898 1.6973340 3.6150778 2.6924143 1.5460727 1.4923351
## Iowa             1.5470089 2.6068606 5.2682765 4.2517889 2.1564575 0.8584962
## Kansas           1.2280424 1.5510864 3.8424558 3.0071474 1.4648766 1.2103118
## Kentucky         2.3346386 2.2514939 3.9474983 2.4408198 2.5203345 1.6565236
## Louisiana        3.5329409 2.3266996 1.7529677 0.8592544 3.5687157 3.5283772
## Maine            1.8792141 2.6560808 5.3946798 4.3334217 2.7160558 0.8486112
## Maryland         3.4968269 1.9624834 1.4355204 1.8388691 3.6148670 3.4014584
## Massachusetts    0.9468199 1.4382527 3.7753087 3.6706708 1.3276676 2.2201020
## Michigan         3.7037870 2.5165292 1.3357020 1.9185489 3.4123472 3.7775301
## Minnesota        0.9843793 2.1652930 4.7635252 3.9621842 1.4673850 1.0124936
## Mississippi      4.1762631 3.0510628 3.0886673 1.5828594 4.4777223 3.6002946
## Missouri         2.4383227 1.6723281 2.5182466 2.1021909 2.1832480 2.4697182
## Montana          1.8584328 2.0306850 4.2696476 3.0967288 2.2488801 0.8286936
## Nebraska         1.2116949 1.8113430 4.3082894 3.4295510 1.6628657 0.7515014
## Nevada           4.5868149 3.5920897 1.9500388 2.9023041 4.0281974 4.7300228
## New Hampshire    1.6169000 2.6744233 5.3778074 4.3427351 2.3112009 0.9249563
## New Jersey       1.6108823 1.5808719 3.1900596 3.1989350 1.5050500 2.7425260
## New Mexico       3.6233659 2.2271650 1.2965798 1.9015384 3.5506088 3.5883476
## New York         3.0239174 1.8992106 1.5730970 2.3634498 2.9055803 3.5910319
## North Carolina   4.1894604 2.7475286 2.9994188 2.3351307 4.7330517 3.5929592
## North Dakota     2.5099838 3.3615239 6.0356613 4.8596758 3.1974906 1.4144557
## Ohio             1.4443671 1.5838515 3.3897305 2.8043208 1.1494313 1.9647327
## Oklahoma         1.4510623 1.1802929 3.3553471 2.7121515 1.6585736 1.5168111
## Oregon           2.1756954 1.7742778 3.3399718 2.9998878 2.0031861 1.9757247
## Pennsylvania     0.8721491 1.5894850 3.9389869 3.1817981 1.2119256 1.5171866
## Rhode Island     1.0756115 1.6230495 4.2314871 4.1832075 2.0590981 2.4592705
## South Carolina   4.0127954 2.7039667 2.5295912 1.3970074 4.2531214 3.4549959
## South Dakota     2.2397424 2.6722813 5.1015141 3.8729745 2.8044891 0.8070290
## Tennessee        3.2302375 2.3195070 2.3992285 1.0122252 3.0747375 2.9234395
## Texas            2.8734475 2.0031365 1.8537984 1.7575559 2.5901696 3.3172180
## Utah             1.2825907 1.8080931 3.9274528 3.7183994 1.0709720 2.0268663
## Vermont          3.2066152 3.7144653 6.0766416 4.7091538 3.7208347 1.7797462
## Virginia         1.9277004 1.4088230 3.1515587 2.2249559 2.0479238 1.6999289
## Washington       1.6963486 1.6350170 3.5570666 3.3016469 1.5452901 1.8861921
## West Virginia    2.7117590 3.0381601 5.3004067 3.8545331 3.2831874 1.4398440
## Wisconsin        1.0354597 2.4410507 5.1085370 4.2281611 1.6666970 1.2105401
## Wyoming          1.6218573 1.2586225 3.6325811 2.7329062 2.1883414 1.1687896
##                 Illinois   Indiana      Iowa    Kansas  Kentucky Louisiana
## Alaska                                                                    
## Arizona                                                                   
## Arkansas                                                                  
## California                                                                
## Colorado                                                                  
## Connecticut                                                               
## Delaware                                                                  
## Florida                                                                   
## Georgia                                                                   
## Hawaii                                                                    
## Idaho                                                                     
## Illinois                                                                  
## Indiana        2.2027081                                                  
## Iowa           3.7380070 1.7786548                                        
## Kansas         2.3228505 0.4287712 1.4699265                              
## Kentucky       2.8478883 1.1790552 1.9426473 1.3020180                    
## Louisiana      1.6535178 2.4957547 4.0359614 2.7284126 2.4221964          
## Maine          3.9342034 2.1029158 0.6457158 1.7913753 1.9925855 4.0901924
## Maryland       1.3429997 2.5430878 4.0642448 2.7400943 2.8229479 1.2739137
## Massachusetts  2.0080982 1.6615695 2.3510287 1.4343401 2.6284451 3.1524549
## Michigan       1.3959090 2.6118471 4.3248636 2.9020920 3.1163494 1.6677999
## Minnesota      3.1558788 1.3184866 0.7644384 0.9745872 1.9333640 3.6905974
## Mississippi    3.0869477 3.0859068 4.1603272 3.2683740 2.3898884 1.6268879
## Missouri       1.3552973 1.2203931 2.9398546 1.5192717 1.9677184 1.8362172
## Montana        2.9659043 1.0033431 1.2403561 0.9170466 0.8523702 2.9444756
## Nebraska       2.7962196 0.8570429 0.9821819 0.5279092 1.4219429 3.1706333
## Nevada         2.3891753 3.5278633 5.2227312 3.8391728 4.1644286 2.8410670
## New Hampshire  3.8490624 1.9278736 0.2058539 1.6084091 2.0093558 4.1168122
## New Jersey     1.4562775 1.7638332 2.9122979 1.7071034 2.6914828 2.6826380
## New Mexico     1.3393276 2.5909993 4.2131394 2.8356373 3.0007332 1.4911656
## New York       0.3502188 2.4628527 4.0411586 2.6096016 3.1213366 1.7495096
## North Carolina 3.0124311 3.3437548 4.2973973 3.4387635 2.8798080 1.9868618
## North Dakota   4.6139615 2.6587932 1.0534375 2.3970805 2.4482563 4.6977846
## Ohio           1.8124981 0.6976320 2.1610242 0.7817000 1.7726720 2.4996969
## Oklahoma       1.8439860 0.5303259 1.9391446 0.5198728 1.4623483 2.3535566
## Oregon         2.0743434 1.1780815 2.4662295 1.3426890 2.1388677 2.7490592
## Pennsylvania   2.3134187 0.8412900 1.5708895 0.5456840 1.5944097 2.8440845
## Rhode Island   2.5057761 2.3335609 2.5453686 2.0087021 3.0457816 3.5648047
## South Carolina 2.6163680 2.8469842 4.1015324 3.0609333 2.4166385 1.3151908
## South Dakota   3.8004708 1.8411735 0.9886706 1.6701106 1.5114990 3.7457555
## Tennessee      1.9478353 1.8100316 3.4176329 2.1533060 1.7489942 1.1298534
## Texas          0.8241352 2.0035762 3.6962443 2.2378289 2.5297839 1.3325285
## Utah           2.2771632 1.4019666 2.1682069 1.2751603 2.5461745 3.3440990
## Vermont        4.8624402 2.8667983 1.7298425 2.7298377 2.3888326 4.6795933
## Virginia       1.8624960 0.6127246 2.1704984 0.8351949 1.0918624 1.9554079
## Washington     2.0612962 1.1405746 2.2502832 1.1579118 2.2630242 2.9705622
## West Virginia  4.1148082 2.2478563 1.5256890 2.1244674 1.5236299 3.7947215
## Wisconsin      3.4790637 1.6806129 0.6318069 1.3242947 2.0950212 3.9559184
## Wyoming        2.2643574 0.8898783 1.7194683 0.7588728 1.0694408 2.3837077
##                    Maine  Maryland Massachusetts  Michigan Minnesota
## Alaska                                                              
## Arizona                                                             
## Arkansas                                                            
## California                                                          
## Colorado                                                            
## Connecticut                                                         
## Delaware                                                            
## Florida                                                             
## Georgia                                                             
## Hawaii                                                              
## Idaho                                                               
## Illinois                                                            
## Indiana                                                             
## Iowa                                                                
## Kansas                                                              
## Kentucky                                                            
## Louisiana                                                           
## Maine                                                               
## Maryland       4.1259083                                            
## Massachusetts  2.6920282 2.9743193                                  
## Michigan       4.5333420 1.0800988     3.0576915                    
## Minnesota      1.2980362 3.6448929     1.6587245 3.7995101          
## Mississippi    4.0014591 2.2992240     4.1217248 2.9722824 4.1067600
## Missouri       3.2055955 1.5705755     1.9810531 1.4068840 2.4088795
## Montana        1.3271199 3.0249456     2.2919046 3.3348908 1.2662635
## Nebraska       1.3218907 3.1309065     1.6863806 3.3478988 0.6083415
## Nevada         5.5153139 2.2551337     3.8556049 1.2609417 4.6391114
## New Hampshire  0.4995971 4.1663744     2.4573524 4.4646172 0.9279247
## New Jersey     3.2532459 2.6263456     0.7977642 2.5678440 2.2254151
## New Mexico     4.3460538 0.5353893     3.0274701 0.5782474 3.7377675
## New York       4.2595904 1.4362170     2.2479437 1.2897453 3.4391596
## North Carolina 4.0631653 2.0542355     4.0773401 3.0232021 4.2219622
## North Dakota   0.7305609 4.7423030     3.3446903 5.1171939 1.8065731
## Ohio           2.5455752 2.5061694     1.1567960 2.4459855 1.5216293
## Oklahoma       2.1929825 2.2492942     1.3383233 2.4336743 1.4198434
## Oregon         2.7813372 2.2466329     1.8709252 2.1626274 1.9270100
## Pennsylvania   1.9197571 2.9585539     1.1337883 3.1048542 1.0106613
## Rhode Island   2.7331079 3.4379146     0.9440940 3.7320501 2.0310592
## South Carolina 4.0015575 1.6165582     3.8310425 2.3233363 3.9484630
## South Dakota   0.7812991 3.7991896     2.8925136 4.1744724 1.4990317
## Tennessee      3.5420469 1.5202431     2.9678843 1.5970196 3.1023238
## Texas          3.9386296 1.5431868     2.2593978 1.2888621 3.1438264
## Utah           2.6218087 3.0338001     0.9015809 2.9441421 1.4177147
## Vermont        1.4253680 4.7430576     3.9277625 5.1250778 2.4019924
## Virginia       2.3474650 2.0124420     1.8503795 2.2439957 1.7932233
## Washington     2.6292546 2.5434911     1.3472994 2.4715215 1.5955418
## West Virginia  1.1818120 4.0251562     3.3782752 4.4668346 2.0791705
## Wisconsin      1.1485830 4.0091486     1.8882704 4.2034334 0.4940832
## Wyoming        1.7665064 2.4041294     1.8201580 2.8324573 1.4845967
##                Mississippi  Missouri   Montana  Nebraska    Nevada
## Alaska                                                            
## Arizona                                                           
## Arkansas                                                          
## California                                                        
## Colorado                                                          
## Connecticut                                                       
## Delaware                                                          
## Florida                                                           
## Georgia                                                           
## Hawaii                                                            
## Idaho                                                             
## Illinois                                                          
## Indiana                                                           
## Iowa                                                              
## Kansas                                                            
## Kentucky                                                          
## Louisiana                                                         
## Maine                                                             
## Maryland                                                          
## Massachusetts                                                     
## Michigan                                                          
## Minnesota                                                         
## Mississippi                                                       
## Missouri         2.8692946                                        
## Montana          3.0015255 2.0313649                              
## Nebraska         3.5269565 1.9651798 0.7389936                    
## Nevada           4.1064793 2.3489003 4.3243112 4.2628916          
## New Hampshire    4.1895936 3.0885710 1.3329504 1.1300720 5.3871427
## New Jersey       3.8894324 1.7079555 2.5912431 2.1246377 3.3464214
## New Mexico       2.6557350 1.4579057 3.1915871 3.2494088 1.7234839
## New York         3.2655822 1.5284764 3.2662661 3.0925340 2.1674148
## North Carolina   1.1826891 3.0224849 3.2209267 3.6500186 4.1773437
## North Dakota     4.4753078 3.7811273 1.8291157 1.9038740 6.0519445
## Ohio             3.4148987 1.1327425 1.6436336 1.2654510 3.2930712
## Oklahoma         3.0466140 1.0927654 1.2225315 0.9674809 3.4108696
## Oregon           3.5033774 0.9974171 1.8044622 1.5727910 2.8581280
## Pennsylvania     3.4971746 1.7793568 1.3246445 0.8483058 4.0392694
## Rhode Island     4.3875001 2.7475003 2.6888576 2.1303973 4.6185330
## South Carolina   0.7865674 2.3846001 2.9024302 3.3517226 3.4427701
## South Dakota     3.5355186 2.8862448 0.8857149 1.2591419 5.1416772
## Tennessee        1.8269569 1.2413874 2.2494023 2.5526834 2.6666268
## Texas            2.8431727 1.1654171 2.8298991 2.7568751 2.2765693
## Utah             4.2571173 1.7478909 2.0956369 1.4573012 3.5868975
## Vermont          4.2046660 3.8803394 1.9261350 2.2952287 6.0437845
## Virginia         2.5383053 0.9787310 1.1556682 1.2472262 3.3001850
## Washington       3.8140404 1.2502752 1.8442691 1.3859985 3.1570805
## West Virginia    3.3281129 3.2538044 1.2758193 1.8117833 5.4963193
## Wisconsin        4.2987974 2.8171535 1.4916365 0.9719877 5.0751736
## Wyoming          2.6813279 1.6073860 0.8150071 0.9268202 3.9202716
##                New Hampshire New Jersey New Mexico  New York North Carolina
## Alaska                                                                     
## Arizona                                                                    
## Arkansas                                                                   
## California                                                                 
## Colorado                                                                   
## Connecticut                                                                
## Delaware                                                                   
## Florida                                                                    
## Georgia                                                                    
## Hawaii                                                                     
## Idaho                                                                      
## Illinois                                                                   
## Indiana                                                                    
## Iowa                                                                       
## Kansas                                                                     
## Kentucky                                                                   
## Louisiana                                                                  
## Maine                                                                      
## Maryland                                                                   
## Massachusetts                                                              
## Michigan                                                                   
## Minnesota                                                                  
## Mississippi                                                                
## Missouri                                                                   
## Montana                                                                    
## Nebraska                                                                   
## Nevada                                                                     
## New Hampshire                                                              
## New Jersey         3.0269198                                               
## New Mexico         4.3360809  2.6208087                                    
## New York           4.1586415  1.6344744  1.3324096                         
## North Carolina     4.3157112  3.9418824  2.5348334 3.2163998               
## North Dakota       0.9231894  3.9166205  4.9450519 4.9325292      4.5836787
## Ohio               2.3095495  1.1099823  2.4960904 2.0434995      3.6205693
## Oklahoma           2.0697098  1.4711183  2.3426252 2.1367108      3.1366639
## Oregon             2.6377191  1.9738854  2.1553130 2.2727718      3.5095191
## Pennsylvania       1.6822035  1.4216058  3.0619915 2.5949374      3.6803956
## Rhode Island       2.5813199  1.4668378  3.6032966 2.7682543      4.2185789
## South Carolina     4.1596914  3.5826726  1.9596343 2.7755634      1.0476313
## South Dakota       0.9874611  3.3318222  3.9969513 4.1124693      3.6955387
## Tennessee          3.5298430  2.6339707  1.5528304 2.0847931      2.3374653
## Texas              3.8178258  1.6226525  1.4418241 0.8457697      3.0857436
## Utah               2.3304873  1.3141843  2.9843796 2.4826984      4.2680823
## Vermont            1.6716127  4.4005416  4.9416825 5.1704762      4.3880034
## Virginia           2.2878085  1.8255601  2.1341562 2.1439207      2.7517523
## Washington         2.4214987  1.5759539  2.4796057 2.2747965      3.8055684
## West Virginia      1.4648924  3.7402121  4.2681325 4.4279608      3.5978058
## Wisconsin          0.7155628  2.4671212  4.1327758 3.7687073      4.4429456
## Wyoming            1.7950754  2.0372127  2.6286722 2.5890441      2.7501141
##                North Dakota      Ohio  Oklahoma    Oregon Pennsylvania
## Alaska                                                                
## Arizona                                                               
## Arkansas                                                              
## California                                                            
## Colorado                                                              
## Connecticut                                                           
## Delaware                                                              
## Florida                                                               
## Georgia                                                               
## Hawaii                                                                
## Idaho                                                                 
## Illinois                                                              
## Indiana                                                               
## Iowa                                                                  
## Kansas                                                                
## Kentucky                                                              
## Louisiana                                                             
## Maine                                                                 
## Maryland                                                              
## Massachusetts                                                         
## Michigan                                                              
## Minnesota                                                             
## Mississippi                                                           
## Missouri                                                              
## Montana                                                               
## Nebraska                                                              
## Nevada                                                                
## New Hampshire                                                         
## New Jersey                                                            
## New Mexico                                                            
## New York                                                              
## North Carolina                                                        
## North Dakota                                                          
## Ohio              3.1448279                                           
## Oklahoma          2.8246690 0.6483903                                 
## Oregon            3.2862071 1.2407607 1.0734082                       
## Pennsylvania      2.5555137 0.7781298 0.8180221 1.7293732             
## Rhode Island      3.4042300 1.9659747 1.9746699 2.6621371    1.6369255
## South Carolina    4.5104172 3.1289884 2.7470931 3.0134453    3.3429642
## South Dakota      1.0324944 2.4394250 2.0340486 2.4988870    1.9790714
## Tennessee         4.0623149 2.0167804 1.8500296 2.0306758    2.4343114
## Texas             4.5749422 1.6711510 1.8312655 2.1053000    2.2460705
## Utah              3.1738212 1.0154223 1.2372916 1.2825152    1.2529078
## Vermont           0.9824857 3.4825859 3.1010306 3.4262789    3.0270572
## Virginia          2.9443461 0.9774388 0.5646254 1.2664430    1.1769236
## Washington        3.1725909 0.9725013 0.9586525 0.5935343    1.3993323
## West Virginia     1.2716808 2.8650371 2.4631736 3.0349855    2.3799278
## Wisconsin         1.6216339 1.8649801 1.7916829 2.4088700    1.2204658
## Wyoming           2.4170757 1.3086480 0.7366465 1.6013015    1.0684605
##                Rhode Island South Carolina South Dakota Tennessee     Texas
## Alaska                                                                     
## Arizona                                                                    
## Arkansas                                                                   
## California                                                                 
## Colorado                                                                   
## Connecticut                                                                
## Delaware                                                                   
## Florida                                                                    
## Georgia                                                                    
## Hawaii                                                                     
## Idaho                                                                      
## Illinois                                                                   
## Indiana                                                                    
## Iowa                                                                       
## Kansas                                                                     
## Kentucky                                                                   
## Louisiana                                                                  
## Maine                                                                      
## Maryland                                                                   
## Massachusetts                                                              
## Michigan                                                                   
## Minnesota                                                                  
## Mississippi                                                                
## Missouri                                                                   
## Montana                                                                    
## Nebraska                                                                   
## Nevada                                                                     
## New Hampshire                                                              
## New Jersey                                                                 
## New Mexico                                                                 
## New York                                                                   
## North Carolina                                                             
## North Dakota                                                               
## Ohio                                                                       
## Oklahoma                                                                   
## Oregon                                                                     
## Pennsylvania                                                               
## Rhode Island                                                               
## South Carolina    4.1861320                                                
## South Dakota      3.1262712      3.5215978                                 
## Tennessee         3.5743861      1.4375120    3.0589938                    
## Texas             2.8757996      2.4532276    3.7101039 1.4712840          
## Utah              1.7565845      3.8912317    2.6823382 2.8678113 2.4039834
## Vermont           4.1104165      4.2668977    1.0856574 3.9356721 4.7444455
## Virginia          2.4330133      2.2636538    2.0316897 1.3514491 1.6921625
## Washington        2.1743525      3.3802314    2.5083824 2.3809584 2.1635337
## West Virginia     3.5400858      3.4651680    0.7108812 3.1707450 3.9586581
## Wisconsin         2.0779526      4.2190973    1.5437375 3.4257189 3.4539515
## Wyoming           2.1726807      2.5059056    1.5644785 1.9298669 2.2564704
##                     Utah   Vermont  Virginia Washington West Virginia Wisconsin
## Alaska                                                                         
## Arizona                                                                        
## Arkansas                                                                       
## California                                                                     
## Colorado                                                                       
## Connecticut                                                                    
## Delaware                                                                       
## Florida                                                                        
## Georgia                                                                        
## Hawaii                                                                         
## Idaho                                                                          
## Illinois                                                                       
## Indiana                                                                        
## Iowa                                                                           
## Kansas                                                                         
## Kentucky                                                                       
## Louisiana                                                                      
## Maine                                                                          
## Maryland                                                                       
## Massachusetts                                                                  
## Michigan                                                                       
## Minnesota                                                                      
## Mississippi                                                                    
## Missouri                                                                       
## Montana                                                                        
## Nebraska                                                                       
## Nevada                                                                         
## New Hampshire                                                                  
## New Jersey                                                                     
## New Mexico                                                                     
## New York                                                                       
## North Carolina                                                                 
## North Dakota                                                                   
## Ohio                                                                           
## Oklahoma                                                                       
## Oregon                                                                         
## Pennsylvania                                                                   
## Rhode Island                                                                   
## South Carolina                                                                 
## South Dakota                                                                   
## Tennessee                                                                      
## Texas                                                                          
## Utah                                                                           
## Vermont        3.6546040                                                       
## Virginia       1.7612066 3.0638337                                             
## Washington     0.6940667 3.4804319 1.3809295                                   
## West Virginia  3.2680139 1.0380554 2.3353210  3.0846553                        
## Wisconsin      1.8082282 2.3518637 2.1266497  2.0637823     2.0308890          
## Wyoming        1.8552036 2.6299335 0.7038309  1.5929546     1.8821600 1.7446366

Sekarang kita siap menggunakan fungsi hclust() untuk melakukan klasterisasi menggunakan metode “hierarchical clustering”.

hc <-hclust(d)
hc
## 
## Call:
## hclust(d = d)
## 
## Cluster method   : complete 
## Distance         : euclidean 
## Number of objects: 50

Kita dapat melihat bagaimana metode ini mengelompokkan data secara bersama-sama dengan menggunakan “dendrogram”. Ada beberapa cara untuk melihat berapa banyak kelompok (klaster) yang ada dalam dataset. Dari “dendrogram”, kita dapat mengetahui bahwa pada dasarnya terdapat empat kelompok dalam dataset tersebut. Oleh karena itu, kita menggabungkan keempat kelompok tersebut menjadi satu.

sub_grp <-cutree(hc,k=4)
sub_grp
##        Alabama         Alaska        Arizona       Arkansas     California 
##              1              1              2              3              2 
##       Colorado    Connecticut       Delaware        Florida        Georgia 
##              2              3              3              2              1 
##         Hawaii          Idaho       Illinois        Indiana           Iowa 
##              3              4              2              3              4 
##         Kansas       Kentucky      Louisiana          Maine       Maryland 
##              3              3              1              4              2 
##  Massachusetts       Michigan      Minnesota    Mississippi       Missouri 
##              3              2              3              1              3 
##        Montana       Nebraska         Nevada  New Hampshire     New Jersey 
##              4              4              2              4              3 
##     New Mexico       New York North Carolina   North Dakota           Ohio 
##              2              2              1              4              3 
##       Oklahoma         Oregon   Pennsylvania   Rhode Island South Carolina 
##              3              3              3              3              1 
##   South Dakota      Tennessee          Texas           Utah        Vermont 
##              4              1              2              3              4 
##       Virginia     Washington  West Virginia      Wisconsin        Wyoming 
##              3              3              4              3              3

Kemudian kita menggunakan paket factoextra untuk menggambar plot dari klaster yang terbentuk.

library(factoextra)
## Loading required package: ggplot2
## Welcome! Want to learn more? See two factoextra-related books at https://goo.gl/ve3WBa

Sekarang kita akan menggambar hasilnya. Kita akan menggunakan fungsi fviz_cluster() untuk melakukan itu.

fviz_cluster(list(data =df,cluster=sub_grp))

Klaster dalam data “USArrests” melalui metode klasterisasi hirarkis. Setiap klaster memiliki warna yang unik. Sumbu x mewakili komponen utama pertama (first principal component) dan sumbu y mewakili komponen utama kedua (second principal component) yang dihitung melalui PCA (Principal Component Analysis).

Baik, cukup sekian pembahasan tentang ruang pengantar contoh Data Science.