Proses MA(2)

Bangkitkan model MA(2) dengan 𝜃1 = 0.4 dan 𝜃2 = 0.6 sebanyak

300 data (Manual)

set.seed(1234)
n <- 300
theta1 <- 0.4
theta2 <- 0.6
e <- rnorm(n) 
Y <- numeric(n)

for (t in 3:n) {
  Y[t] <- e[t] + theta1 * e[t-1] + theta2 * e[t-2]
}
Y <- ts(Y) #ubah ke time series
Y
## Time Series:
## Start = 1 
## End = 300 
## Frequency = 1 
##   [1]  0.000000000  0.000000000  0.471173424 -1.745463687  0.141510314
##   [6] -0.729712854 -0.114842790 -0.472894305 -1.127948717 -1.443797742
##  [11] -1.171879031 -1.723286222 -1.461924092 -0.845074607  0.519525249
##  [16]  0.312187420  0.020572732 -1.181770516 -1.508255550  1.534249256
##  [21]  0.598119283  1.012450498 -0.556369299 -0.011041246 -0.774213194
##  [26] -1.449939345 -0.420758391 -1.662676381 -0.079747157 -1.556197355
##  [31]  0.718835126 -0.596243221 -0.238298741 -1.070389923 -2.255260716
##  [36] -2.120011486 -3.624543435 -2.913580609 -2.138714925 -1.388210999
##  [41]  1.086560934 -0.768382742 -0.413123964 -1.263954490 -1.619808057
##  [46] -1.534624150 -2.091327966 -2.276021753 -1.689013389 -1.457572736
##  [51] -2.319068111 -1.602598402 -2.425338748 -1.807763414 -1.233628102
##  [56] -0.110845196  1.775654086  0.223607057  2.285258743 -0.979456751
##  [61]  1.157010823  2.116941328  1.378789117  0.845856907 -0.296314421
##  [66]  1.372262398 -0.432336811  1.978634754  1.193531021  1.688995021
##  [71]  0.939220832 -0.250827924 -0.544575725  0.228395751  2.109671129
##  [76]  1.063681873 -0.209897795 -1.371901203 -0.865591517 -0.647903476
##  [81] -0.149656546 -0.431345529 -1.546973491 -0.824704371 -0.042663743
##  [86]  0.933429312  1.339180190  0.235832192 -0.022688150 -1.512804573
##  [91] -0.645926233 -0.482784254  1.776147116  1.837016456  0.928600262
##  [96]  0.758224871 -1.289737991  0.637690588  0.643433378  3.037205983
## [101]  1.846720429  0.963761203  0.124820225 -0.760911469 -0.987393604
## [106] -0.464896825 -1.325068067 -0.090126895 -0.115516360  0.190793420
## [111] -0.003795709 -0.758706669 -1.486955903  0.015925459 -0.303788132
## [116]  1.349650149 -0.898414089  0.169995644 -0.005795838  0.344405995
## [121]  0.201997065 -0.874229340  1.630564028  1.104622260  3.359306076
## [126]  1.260043834  0.495139539 -1.717816055 -1.620260658 -0.936111272
## [131]  0.722551062  0.794007194 -0.462634050  0.351585084 -2.085784191
## [136] -0.624664025 -1.452519789 -2.294204728 -0.048911894 -1.423796214
## [141] -0.031150775  0.887810276  0.994311578  0.983326803  0.852394746
## [146]  0.539717900  2.130822837  1.180599067  1.614343853  0.715597066
## [151]  0.065546716  0.155255589  1.451449842 -0.161522938  0.754769796
## [156]  0.885479176  0.383287177 -0.329952846 -1.431909381 -1.370070157
## [161] -1.525271048 -0.833655639 -1.027085507 -0.505202316  0.085183955
## [166]  0.677625089  2.172292654  0.977368521  0.658606072  1.301453560
## [171]  2.100227737  1.607579227  0.707237935 -1.929351923  0.482773840
## [176] -1.366418725 -0.612038329  2.091711308  0.778269986  1.887009445
## [181] -2.604510182 -1.212633564 -0.703216214  0.744407256  1.663488769
## [186]  2.596982415  2.509994691  1.149145711  1.202150481 -0.221986412
## [191] -0.194929191 -3.190036735 -2.254792788 -1.541499299  1.889370282
## [196]  1.660596411  2.121307573 -0.417402360  0.148419546 -2.592717585
## [201] -0.248475371 -0.356083018  0.755357519  1.193000349  0.703282784
## [206]  1.305574883  2.333657188  2.305625709  1.583087270 -0.433965677
## [211] -0.008123389 -0.901681487  1.584233701 -1.249824841 -0.162488303
## [216] -0.708540906 -0.232384260 -0.413640706 -0.638223437  0.143957003
## [221]  0.964153779  1.396003084  3.074671761  2.479018560  2.121198870
## [226]  0.159412341  2.827857930  1.449209496  1.338129934  0.319213246
## [231] -0.660388674 -0.292566289 -1.238021008 -0.421378522 -0.194203628
## [236] -0.879770820 -3.472672839 -2.194660779 -2.012323310  0.453156115
## [241]  0.314555376  0.793617226 -0.896931516  0.520105724  0.344695528
## [246]  0.965911715  1.889268102  1.098368887  1.240516320  0.616470695
## [251]  0.702766701  1.395722479  1.138398305  1.480149118 -0.599779870
## [256] -0.427127769  0.646946451 -0.855414425  0.654688641 -0.226112090
## [261]  1.292645476  0.284446275  0.604556738 -1.909130933 -0.271530716
## [266] -1.589079651 -0.302115008 -1.683162950 -0.233358766  0.107894475
## [271]  0.192979110  2.103113218  1.217795463  2.311862960  2.831191653
## [276]  0.737827135  1.777815630  0.919360158  0.873633013  0.908532408
## [281] -0.887903437  0.256870201 -1.119996454  0.815395259 -0.906539838
## [286]  0.483034891 -1.205622129 -0.392733748 -2.159077875 -0.640167479
## [291]  0.105101596  0.654485299 -1.101664171 -1.217076868  0.348092030
## [296]  2.099902382  0.542511208  0.249165265 -0.498077915  0.240584445

Bangkitkan model MA(2) dengan 𝜃1 = 0.4 dan 𝜃2 = 0.6 sebanyak

300 data (arima.sim)

set.seed(1234)
Y_arima <- arima.sim(model = list(ma = c(0.4, 0.6)), n = 300)
Y_arima
## Time Series:
## Start = 1 
## End = 300 
## Frequency = 1 
##   [1]  0.471173424 -1.745463687  0.141510314 -0.729712854 -0.114842790
##   [6] -0.472894305 -1.127948717 -1.443797742 -1.171879031 -1.723286222
##  [11] -1.461924092 -0.845074607  0.519525249  0.312187420  0.020572732
##  [16] -1.181770516 -1.508255550  1.534249256  0.598119283  1.012450498
##  [21] -0.556369299 -0.011041246 -0.774213194 -1.449939345 -0.420758391
##  [26] -1.662676381 -0.079747157 -1.556197355  0.718835126 -0.596243221
##  [31] -0.238298741 -1.070389923 -2.255260716 -2.120011486 -3.624543435
##  [36] -2.913580609 -2.138714925 -1.388210999  1.086560934 -0.768382742
##  [41] -0.413123964 -1.263954490 -1.619808057 -1.534624150 -2.091327966
##  [46] -2.276021753 -1.689013389 -1.457572736 -2.319068111 -1.602598402
##  [51] -2.425338748 -1.807763414 -1.233628102 -0.110845196  1.775654086
##  [56]  0.223607057  2.285258743 -0.979456751  1.157010823  2.116941328
##  [61]  1.378789117  0.845856907 -0.296314421  1.372262398 -0.432336811
##  [66]  1.978634754  1.193531021  1.688995021  0.939220832 -0.250827924
##  [71] -0.544575725  0.228395751  2.109671129  1.063681873 -0.209897795
##  [76] -1.371901203 -0.865591517 -0.647903476 -0.149656546 -0.431345529
##  [81] -1.546973491 -0.824704371 -0.042663743  0.933429312  1.339180190
##  [86]  0.235832192 -0.022688150 -1.512804573 -0.645926233 -0.482784254
##  [91]  1.776147116  1.837016456  0.928600262  0.758224871 -1.289737991
##  [96]  0.637690588  0.643433378  3.037205983  1.846720429  0.963761203
## [101]  0.124820225 -0.760911469 -0.987393604 -0.464896825 -1.325068067
## [106] -0.090126895 -0.115516360  0.190793420 -0.003795709 -0.758706669
## [111] -1.486955903  0.015925459 -0.303788132  1.349650149 -0.898414089
## [116]  0.169995644 -0.005795838  0.344405995  0.201997065 -0.874229340
## [121]  1.630564028  1.104622260  3.359306076  1.260043834  0.495139539
## [126] -1.717816055 -1.620260658 -0.936111272  0.722551062  0.794007194
## [131] -0.462634050  0.351585084 -2.085784191 -0.624664025 -1.452519789
## [136] -2.294204728 -0.048911894 -1.423796214 -0.031150775  0.887810276
## [141]  0.994311578  0.983326803  0.852394746  0.539717900  2.130822837
## [146]  1.180599067  1.614343853  0.715597066  0.065546716  0.155255589
## [151]  1.451449842 -0.161522938  0.754769796  0.885479176  0.383287177
## [156] -0.329952846 -1.431909381 -1.370070157 -1.525271048 -0.833655639
## [161] -1.027085507 -0.505202316  0.085183955  0.677625089  2.172292654
## [166]  0.977368521  0.658606072  1.301453560  2.100227737  1.607579227
## [171]  0.707237935 -1.929351923  0.482773840 -1.366418725 -0.612038329
## [176]  2.091711308  0.778269986  1.887009445 -2.604510182 -1.212633564
## [181] -0.703216214  0.744407256  1.663488769  2.596982415  2.509994691
## [186]  1.149145711  1.202150481 -0.221986412 -0.194929191 -3.190036735
## [191] -2.254792788 -1.541499299  1.889370282  1.660596411  2.121307573
## [196] -0.417402360  0.148419546 -2.592717585 -0.248475371 -0.356083018
## [201]  0.755357519  1.193000349  0.703282784  1.305574883  2.333657188
## [206]  2.305625709  1.583087270 -0.433965677 -0.008123389 -0.901681487
## [211]  1.584233701 -1.249824841 -0.162488303 -0.708540906 -0.232384260
## [216] -0.413640706 -0.638223437  0.143957003  0.964153779  1.396003084
## [221]  3.074671761  2.479018560  2.121198870  0.159412341  2.827857930
## [226]  1.449209496  1.338129934  0.319213246 -0.660388674 -0.292566289
## [231] -1.238021008 -0.421378522 -0.194203628 -0.879770820 -3.472672839
## [236] -2.194660779 -2.012323310  0.453156115  0.314555376  0.793617226
## [241] -0.896931516  0.520105724  0.344695528  0.965911715  1.889268102
## [246]  1.098368887  1.240516320  0.616470695  0.702766701  1.395722479
## [251]  1.138398305  1.480149118 -0.599779870 -0.427127769  0.646946451
## [256] -0.855414425  0.654688641 -0.226112090  1.292645476  0.284446275
## [261]  0.604556738 -1.909130933 -0.271530716 -1.589079651 -0.302115008
## [266] -1.683162950 -0.233358766  0.107894475  0.192979110  2.103113218
## [271]  1.217795463  2.311862960  2.831191653  0.737827135  1.777815630
## [276]  0.919360158  0.873633013  0.908532408 -0.887903437  0.256870201
## [281] -1.119996454  0.815395259 -0.906539838  0.483034891 -1.205622129
## [286] -0.392733748 -2.159077875 -0.640167479  0.105101596  0.654485299
## [291] -1.101664171 -1.217076868  0.348092030  2.099902382  0.542511208
## [296]  0.249165265 -0.498077915  0.240584445 -0.240119231 -0.993767765

Buat plot time series, plot ACF, plot PACF dan plot EACF. Idenifikasi

apakah data tersebut stasioner

Plot Time Series

plot(Y, main = "MA(2) Time Series", ylab = "Yt", xlab = "Time")

Plot ACF

acf(Y, main = "ACF of MA(2)")

Plot PACF

pacf(Y, main = "PACF of MA(2)")

Plot EACF

library(TSA)
## Warning: package 'TSA' was built under R version 4.3.3
## 
## Attaching package: 'TSA'
## The following objects are masked from 'package:stats':
## 
##     acf, arima
## The following object is masked from 'package:utils':
## 
##     tar
eacf(Y)
## AR/MA
##   0 1 2 3 4 5 6 7 8 9 10 11 12 13
## 0 x x o o o o o o o o o  o  x  x 
## 1 x x x o o o o o o o o  o  o  o 
## 2 x x x x o o o o o o o  o  o  o 
## 3 x x x x o o o o o o o  o  o  o 
## 4 x x x x x o o o o o o  o  o  o 
## 5 x x x x x o x o o o o  o  o  o 
## 6 x x x o x o o x o o o  o  o  o 
## 7 x o x o x o o x o o o  o  o  o

Identifikasi Stasioner

polyroot(c(1, -0.4, -0.6))  # contoh model MA(2) dengan 𝜃1 = 0.4 dan 𝜃2 = 0.6
## [1]  1.000000-0i -1.666667+0i

Buat scatterplot antara 𝑌𝑡 dengan 𝑌𝑡−1, 𝑌𝑡 dengan 𝑌𝑡−2 serta 𝑌𝑡

dengan 𝑌𝑡−3

Scatterplot Yt dengan Yt-1

plot(Y[2:300], Y[1:299], main = "Scatterplot Yt vs Yt-1", xlab = "Yt-1", ylab = "Yt")

Scatterplot Yt dengan Yt-2

plot(Y[3:300], Y[1:298], main = "Scatterplot Yt vs Yt-2", xlab = "Yt-2", ylab = "Yt")

Scatterplot Yt dengan Yt-3

plot(Y[4:300], Y[1:297], main = "Scatterplot Yt vs Yt-3", xlab = "Yt-3", ylab = "Yt")

Hitung autokorelasi masing masing baik dari data bangkitan maupun secara teoritis

Autokorelasi Empiris

acf(Y)

Autokorelasi Teoritis

rho1 <- theta1 / (1 + theta1^2 + theta2^2)
rho2 <- theta2 / (1 + theta1^2 + theta2^2)
rho1  # Lag 1 autokorelasi
## [1] 0.2631579
rho2  # Lag 2 autokorelasi
## [1] 0.3947368

Proses AR(2)

Bangkitkan model AR(2) dengan 𝜙1 = 0.5 dan 𝜙2 = 0.2 sebanyak

300 data (Manual)

set.seed(2045)
n <- 300
phi1 <- 0.5
phi2 <- 0.2
e <- rnorm(n) 
Y <- numeric(n)

for (t in 3:n) {
  Y[t] <- phi1 * Y[t-1] + phi2 * Y[t-2] + e[t]
}
Y <- ts(Y)  # ubah ke time series
Y
## Time Series:
## Start = 1 
## End = 300 
## Frequency = 1 
##   [1]  0.000000000  0.000000000  0.349020405  1.270425965  0.017362695
##   [6]  1.474514746  2.596405374  2.319602862  2.153949875  0.278376633
##  [11]  0.912608295 -0.366786480 -1.573453956  1.437720486 -0.552850198
##  [16] -1.345251829  0.825378964  1.088179363  0.589119857  0.350507953
##  [21] -0.961247294 -0.384974917 -0.462455657 -1.106286974 -0.398312256
##  [26] -2.548595257 -2.023777688 -1.529759184 -1.252899760 -0.098629642
##  [31] -1.217998097 -2.068706922 -2.612921715 -1.605997949 -1.206676609
##  [36]  0.100573712  0.296889935  2.213252575  1.304099028  1.818767455
##  [41]  0.718669521 -0.042567024  1.131770309 -0.063905989  0.110665093
##  [46] -0.536175954 -0.464512163 -1.754010488 -0.179975774 -0.148920498
##  [51] -0.119640196  0.349312384  1.222631169 -0.474740673 -1.350357255
##  [56] -0.436715506 -1.637800653 -0.024276175 -0.397876145  0.430292208
##  [61] -1.176418631 -0.278187905  0.528451376  0.396331205  0.756909308
##  [66]  1.294856282  1.155846487 -0.822637995 -1.278652933 -1.693699790
##  [71] -1.648627171 -0.775305761 -1.773598338 -1.557341727 -0.767990769
##  [76] -1.485018115 -1.652698099 -2.548366279 -0.627212756 -2.371863661
##  [81] -1.311007654 -1.287429345  1.560994051  2.209376465  1.540482426
##  [86] -0.017561349 -0.566208334 -0.202630946  1.051230863  0.276965668
##  [91]  1.325417529  0.845468334  0.220523476  1.631390439  0.537581507
##  [96]  0.726615580 -0.264136582 -0.712478821 -1.499169555 -0.338776967
## [101] -2.259311778 -1.539737525 -3.047990681 -1.264124635 -0.955427324
## [106] -0.181308526 -1.187961743  0.508909767  0.799150781  0.466130367
## [111]  0.990659051  0.912713747  0.713904156  0.624013578  1.307770701
## [116]  0.879917311  1.773883285  0.692647268  1.050279788  1.793408686
## [121]  1.900245965 -0.189361354 -0.082761708 -0.241123849 -0.262185962
## [126] -0.144812882  0.429232814 -0.770622830 -1.212353609 -0.970526724
## [131] -0.329333629  0.216480677  0.077560660  0.960968454 -0.798930504
## [136]  0.228057490 -0.758582354 -1.431085323 -1.627825976 -1.220806258
## [141] -1.100277332 -0.004178275  1.154885048  2.485164950  1.795042409
## [146]  1.138274537  1.289111387  1.023972788 -0.504250538  0.428296980
## [151] -0.281177386  1.152998624  1.149967889 -0.098607504  0.673731822
## [156]  2.045183555  2.224055194  1.485682007  0.424982863 -0.434563725
## [161] -0.725783878 -0.726177063 -1.132231088 -0.009038700  0.674843742
## [166] -0.321853748  0.939558171 -0.856933542 -2.484562816 -1.179468992
## [171] -2.869532925 -2.383501302  0.013953327  0.504269014  0.420271938
## [176] -0.807755968 -1.592064335  1.308270116 -0.106099037 -1.205737648
## [181]  0.705752391 -0.297404289  1.374343783 -0.573189714 -0.085318873
## [186]  0.244207194 -1.599592854 -0.349845558 -0.056991413  0.315291394
## [191]  1.048847433  0.662831772  0.959636404  0.294246989  0.034575587
## [196]  0.137871293 -0.883018780 -0.867146848  0.248802076 -0.232012155
## [201]  1.002976050  0.484213173  1.626911963  0.860741733  0.351823963
## [206]  1.459381221  0.844250125  2.912962318  3.477182751  3.271074924
## [211]  0.486826876  0.854291297  0.371641491  1.270969422  0.715391739
## [216]  2.073519283  0.660422091  1.320845178 -0.650887420 -0.224463500
## [221] -0.599988230  0.790442044  1.472566343  0.675874551  0.428479628
## [226]  1.827851685  1.261117783  1.045867094  0.882852385 -2.334116955
## [231] -2.103603557 -0.658874256 -1.942833888  0.615523016 -0.006842329
## [236]  0.995076257  1.694676891  0.433146991  2.125971999  1.478629905
## [241]  3.083769633  1.915815714  2.425950795  3.182572762  2.738938326
## [246]  2.872239794  1.131842641  1.258204028  1.504419774  0.420148676
## [251]  0.012389324 -0.330958229 -1.558435697 -0.486396443 -0.704596653
## [256] -1.772139555  0.409627494  0.449945403  0.830116243  0.666561563
## [261]  2.349910446  1.825761859  1.701351434  2.603741729  0.937504850
## [266] -0.099971818  0.178723265  0.122184822  1.686884383 -0.385524912
## [271]  0.229673936  0.856964087 -0.105920342 -1.174953821  0.051775014
## [276]  0.591220110 -0.558995867 -0.197546961  1.176973506  0.057601942
## [281]  0.956296804 -1.343840432 -0.485971570  0.494059269 -0.155562760
## [286]  0.102526731 -1.133036582  0.729583434  0.370684823  0.888165023
## [291]  1.007059306  1.256546000  0.924997834 -0.550435936  0.534597153
## [296]  2.580043778  2.337655235  0.998758660  0.652649717  0.941998246

Bangkitkan model AR(2) dengan 𝜙1 = 0.5 dan 𝜙2 = 0.2 sebanyak

300 data (arima.sim)

set.seed(2045)
Y_arima <- arima.sim(model = list(ar = c(0.5, 0.2)), n = 300)
Y_arima
## Time Series:
## Start = 1 
## End = 300 
## Frequency = 1 
##   [1] -2.548034118 -2.023349904 -1.529433064 -1.252651144 -0.098440109
##   [6] -1.217853608 -2.068596771 -2.612837741 -1.605933932 -1.206627806
##  [11]  0.100610917  0.296918298  2.213274198  1.304115512  1.818780021
##  [16]  0.718679101 -0.042559721  1.131775877 -0.063901745  0.110668328
##  [21] -0.536173487 -0.464510283 -1.754009054 -0.179974681 -0.148919665
##  [26] -0.119639560  0.349312868  1.222631538 -0.474740392 -1.350357040
##  [31] -0.436715343 -1.637800528 -0.024276080 -0.397876073  0.430292263
##  [36] -1.176418589 -0.278187873  0.528451401  0.396331223  0.756909322
##  [41]  1.294856293  1.155846495 -0.822637989 -1.278652928 -1.693699786
##  [46] -1.648627168 -0.775305758 -1.773598336 -1.557341726 -0.767990768
##  [51] -1.485018114 -1.652698099 -2.548366279 -0.627212755 -2.371863661
##  [56] -1.311007654 -1.287429345  1.560994051  2.209376465  1.540482426
##  [61] -0.017561349 -0.566208334 -0.202630946  1.051230864  0.276965668
##  [66]  1.325417529  0.845468334  0.220523476  1.631390439  0.537581507
##  [71]  0.726615580 -0.264136582 -0.712478821 -1.499169555 -0.338776967
##  [76] -2.259311778 -1.539737525 -3.047990681 -1.264124635 -0.955427324
##  [81] -0.181308526 -1.187961743  0.508909767  0.799150781  0.466130367
##  [86]  0.990659051  0.912713747  0.713904156  0.624013578  1.307770701
##  [91]  0.879917311  1.773883285  0.692647268  1.050279788  1.793408686
##  [96]  1.900245965 -0.189361354 -0.082761708 -0.241123849 -0.262185962
## [101] -0.144812882  0.429232814 -0.770622830 -1.212353609 -0.970526724
## [106] -0.329333629  0.216480677  0.077560660  0.960968454 -0.798930504
## [111]  0.228057490 -0.758582354 -1.431085323 -1.627825976 -1.220806258
## [116] -1.100277332 -0.004178275  1.154885048  2.485164950  1.795042409
## [121]  1.138274537  1.289111387  1.023972788 -0.504250538  0.428296980
## [126] -0.281177386  1.152998624  1.149967889 -0.098607504  0.673731822
## [131]  2.045183555  2.224055194  1.485682007  0.424982863 -0.434563725
## [136] -0.725783878 -0.726177063 -1.132231088 -0.009038700  0.674843742
## [141] -0.321853748  0.939558171 -0.856933542 -2.484562816 -1.179468992
## [146] -2.869532925 -2.383501302  0.013953327  0.504269014  0.420271938
## [151] -0.807755968 -1.592064335  1.308270116 -0.106099037 -1.205737648
## [156]  0.705752391 -0.297404289  1.374343783 -0.573189714 -0.085318873
## [161]  0.244207194 -1.599592854 -0.349845558 -0.056991413  0.315291394
## [166]  1.048847433  0.662831772  0.959636404  0.294246989  0.034575587
## [171]  0.137871293 -0.883018780 -0.867146848  0.248802076 -0.232012155
## [176]  1.002976050  0.484213173  1.626911963  0.860741733  0.351823963
## [181]  1.459381221  0.844250125  2.912962318  3.477182751  3.271074924
## [186]  0.486826876  0.854291297  0.371641491  1.270969422  0.715391739
## [191]  2.073519283  0.660422091  1.320845178 -0.650887420 -0.224463500
## [196] -0.599988230  0.790442044  1.472566343  0.675874551  0.428479628
## [201]  1.827851685  1.261117783  1.045867094  0.882852385 -2.334116955
## [206] -2.103603557 -0.658874256 -1.942833888  0.615523016 -0.006842329
## [211]  0.995076257  1.694676891  0.433146991  2.125971999  1.478629905
## [216]  3.083769633  1.915815714  2.425950795  3.182572762  2.738938326
## [221]  2.872239794  1.131842641  1.258204028  1.504419774  0.420148676
## [226]  0.012389324 -0.330958229 -1.558435697 -0.486396443 -0.704596653
## [231] -1.772139555  0.409627494  0.449945403  0.830116243  0.666561563
## [236]  2.349910446  1.825761859  1.701351434  2.603741729  0.937504850
## [241] -0.099971818  0.178723265  0.122184822  1.686884383 -0.385524912
## [246]  0.229673936  0.856964087 -0.105920342 -1.174953821  0.051775014
## [251]  0.591220110 -0.558995867 -0.197546961  1.176973506  0.057601942
## [256]  0.956296804 -1.343840432 -0.485971570  0.494059269 -0.155562760
## [261]  0.102526731 -1.133036582  0.729583434  0.370684823  0.888165023
## [266]  1.007059306  1.256546000  0.924997834 -0.550435936  0.534597153
## [271]  2.580043778  2.337655235  0.998758660  0.652649717  0.941998246
## [276]  0.527504110  1.111115683 -0.627950139 -0.941101697 -1.723258979
## [281] -0.684048818 -0.572227212  0.650246462  1.384110378  0.439484383
## [286] -0.961953461 -0.572682964 -0.689930160 -0.834167422 -1.504773911
## [291]  1.062257278 -0.590214172 -0.427143672 -1.854268270 -0.859444018
## [296] -0.245741525 -0.220231163  3.066928007  0.848696962  1.205644524

Buat plot time series, plot ACF, plot PACF dan plot EACF. Idenifikasi apakah data tersebut stasioner

Plot Time Series

plot(Y, main = "AR(2) Time Series", ylab = "Yt", xlab = "Time")

Plot ACF

acf(Y, main = "ACF of AR(2)")

Plot PACF

pacf(Y, main = "PACF of AR(2)")

Plot EACF

library(TSA)
eacf(Y)
## AR/MA
##   0 1 2 3 4 5 6 7 8 9 10 11 12 13
## 0 x x x x x o o o o o o  o  o  x 
## 1 x o o o o o o o o o o  o  o  o 
## 2 x x o o o o o o o o o  o  o  o 
## 3 x x o o o o o o o o o  o  o  o 
## 4 x x x o o o o o o o o  o  o  o 
## 5 x x o o o o o o o o o  o  o  o 
## 6 x x o o x o o o o o o  o  o  o 
## 7 x x o o x x o o o o o  o  o  o

Identifikasi Stasioneritas

polyroot(c(1, -0.5, -0.2))  # Untuk 𝜙1 = 0.5 dan 𝜙2 = 0.2
## [1]  1.311738+0i -3.811738+0i

Buat scatterplot antara 𝑌𝑡 dengan 𝑌𝑡−1, 𝑌𝑡 dengan 𝑌𝑡−2 serta 𝑌𝑡

dengan 𝑌𝑡−3

Scatterplot Yt dengan Yt-1

plot(Y[2:300], Y[1:299], main = "Scatterplot Yt vs Yt-1", xlab = "Yt-1", ylab = "Yt")

Scatterplot Yt dengan Yt-2

plot(Y[3:300], Y[1:298], main = "Scatterplot Yt vs Yt-2", xlab = "Yt-2", ylab = "Yt")

Scatterplot Yt dengan Yt-3

plot(Y[4:300], Y[1:297], main = "Scatterplot Yt vs Yt-3", xlab = "Yt-3", ylab = "Yt")

Hitung autokorelasi masing masing baik dari data bangkitan maupun secara teoritis

Autokorelasi Teoritis menggunakan persamaan Yule-Walker

phi1 <- 0.5
phi2 <- 0.2

Lag 1 dan Lag 2

rho1 <- phi1 / (1 - phi2)
rho2 <- (phi1 * rho1 + phi2) / (1 - phi2)
rho1  # Lag 1 autokorelasi teoritis
## [1] 0.625
rho2  # Lag 2 autokorelasi teoritis
## [1] 0.640625

Proses ARMA (2,2)

Bangkitkan model ARMA(2,2) dengan 𝜃1 = 0.4, 𝜃2 = 0.6 ,𝜙1 = 0.5

dan 𝜙2 = 0.2 sebanyak 300 data (Manual)

set.seed(2045)
n <- 300
phi1 <- 0.5
phi2 <- 0.2
theta1 <- 0.4
theta2 <- 0.6
e <- rnorm(n)
Y <- numeric(n)

for (t in 3:n) {
  Y[t] <- phi1 * Y[t-1] + phi2 * Y[t-2] + e[t] - theta1 * e[t-1] - theta2 * e[t-2]
}
Y <- ts(Y)  # convert to time series
Y
## Time Series:
## Start = 1 
## End = 300 
## Frequency = 1 
##   [1]  0.00000000  0.00000000 -0.07756096  0.95904978 -0.87142022  0.58536034
##   [7]  1.90196493  0.32523265 -0.38612749 -2.01638137 -0.52269905 -0.92293243
##  [13] -1.99266002  2.27318079 -0.19453374 -1.99487654  1.68899002  1.56045248
##  [19] -0.34498242 -0.54079446 -1.45701645 -0.21237717  0.26706567 -0.69124755
##  [25]  0.32096863 -1.72603738 -0.76576329  0.80859567  0.57303163  1.32020365
##  [31] -0.42694523 -1.52243574 -1.05472078  0.68033338  1.00342870  1.54680737
##  [37]  0.98063916  2.03413160  0.24064820 -0.03083578 -0.79130608 -1.42130232
##  [43]  0.71759006 -0.49107798 -0.54283781 -0.54210077 -0.31644264 -1.24650143
##  [49]  0.80033467  0.97547530  0.04791286  0.48652030  1.15468998 -1.17338084
##  [55] -1.89403989  0.38827164 -0.65290022  0.89287330  0.59451465  0.60400832
##  [61] -1.10980987 -0.06579581  1.34557769  0.35186338  0.28130599  0.75429383
##  [67]  0.18375838 -2.06189036 -1.64310563 -0.68865582 -0.20395550  0.90036498
##  [73] -0.47429973 -0.38271894  0.91910492 -0.24341677 -0.59789639 -0.99627617
##  [79]  1.38375262 -0.59195879  0.01406546  0.66009191  2.86257038  2.35743645
##  [85] -0.27986459 -1.95938020 -1.48347325  0.03438920  1.47200824 -0.02194811
##  [91]  0.58389274  0.14912192 -0.91291438  1.03590005 -0.24728875 -0.46725129
##  [97] -0.87733172 -1.04279354 -1.05569608  0.68837815 -1.22429926 -0.43274663
## [103] -1.07650860  0.87891415  1.37901694  0.95933718 -0.54218194  1.09287958
## [109]  1.30836392 -0.15887581  0.32471644  0.23677191 -0.24557677 -0.20917633
## [115]  0.62982278 -0.01759912  0.63725394 -0.54485643 -0.29110909  0.95770841
## [121]  0.55271462 -2.02550495 -1.14716475 -0.09440235 -0.11607940  0.10473581
## [127]  0.64446954 -0.85542823 -1.16164417 -0.02321158  0.78628923  0.93053016
## [133]  0.18856857  0.80005578 -1.22985428 -0.02895138 -0.37044705 -1.26448688
## [139] -0.60024243  0.28897533  0.36474076  1.16841641  1.81672276  2.02571790
## [145]  0.10804540 -1.07084140 -0.24322387 -0.17463649 -1.68730649  0.01561352
## [151] -0.14994585  1.00849139  0.85747487 -1.25039383  0.02319409  1.83485533
## [157]  1.00174268 -0.63105020 -1.50372306 -1.49596608 -0.80694811 -0.17512528
## [163] -0.40628994  0.87955997  1.35779787 -0.58636803  0.66339343 -1.03964456
## [169] -2.70552430  0.32851626 -0.90700764 -0.52800674  2.68907360  1.92878846
## [175]  0.21019234 -1.27842615 -1.52112511  2.42974943  0.32583152 -1.94826010
## [181]  1.25170687  0.14373734  1.06985406 -0.94448465 -0.68064926  0.62224857
## [187] -1.64608441  0.14346727  1.04270252  0.54799529  0.95692572  0.05411796
## [193]  0.06519524 -0.48730664 -0.65890505 -0.05250713 -0.95891265 -0.59666211
## [199]  1.12547208  0.18875512  0.94649967  0.22223005  0.83144106 -0.08055096
## [205] -0.96861991  0.80220660  0.04940326  1.69963354  1.80544775  0.13242443
## [211] -2.90791274 -1.30308441 -0.26217115  0.60973805 -0.01598092  1.02478093
## [217] -0.59822067 -0.18743523 -1.57547875 -0.75661564 -0.11967038  1.16511544
## [223]  1.51638246 -0.38741721 -0.72541000  1.25093510  0.27288933 -0.55529103
## [229] -0.29216512 -3.31477817 -1.69966821  1.58303734 -0.41712205  1.78798112
## [235]  0.91264880  0.62849938  1.30075179 -0.84176952  0.93590707  0.36835291
## [241]  1.21673447 -0.20487008 -0.19063727  1.06270302  0.01033874 -0.13287919
## [247] -1.66041627 -0.91787690  0.32203258 -0.93654165 -1.05832201 -0.58800316
## [253] -1.43348600  0.33555277  0.42502334 -1.19846303  1.54124131  1.34937814
## [259]  0.40436159  0.06454782  1.58521607  0.48586074 -0.43889958  0.82774404
## [265] -1.12480270 -2.03721880 -0.34379092  0.11067861  1.53077650 -1.13358956
## [271] -0.62824673  0.99640946 -0.58651034 -1.64676414  0.58530875  1.27548240
## [277] -0.82654892 -0.32868068  1.59138981 -0.29465928  0.22707192 -1.76092032
## [283] -0.52221348  1.49475216 -0.06160353 -0.13168373 -1.08070962  1.12128203
## [289]  0.75867340  0.30214103  0.42938240  0.32082326 -0.18185615 -1.67436267
## [295]  0.19977283  2.69646648  0.98487943 -1.48432970 -1.14944689  0.08168316

Bangkitkan model ARMA(2,2) dengan 𝜃1 = 0.4, 𝜃2 = 0.6 ,𝜙1 = 0.5

dan 𝜙2 = 0.2 sebanyak 300 data (arima.sim)

set.seed(2045)
Y_arima <- arima.sim(model = list(ar = c(0.5, 0.2), ma = c(0.4, 0.6)), n = 300)
Y_arima
## Time Series:
## Start = 1 
## End = 300 
## Frequency = 1 
##   [1] -3.868114041 -3.078831148 -1.517462932 -2.009050969 -2.614978100
##   [6] -4.171122651 -3.892329273 -3.416781922 -1.345659950 -0.386859291
##  [11]  2.392373554  2.367549859  3.668370686  2.228645125  1.336168275
##  [16]  1.545950562  0.363265998  0.764167992 -0.530251140 -0.612581682
##  [21] -2.261519548 -1.160286217 -1.273316299 -0.287193249  0.212104473
##  [26]  1.290572360  0.223899495 -0.806674617 -1.261702655 -2.622701089
##  [31] -0.941425649 -1.390266937  0.256576098 -1.243027394 -0.490580002
##  [36] -0.288674941  0.440799030  1.232512629  1.835418738  2.127934592
##  [41]  0.416614375 -0.914200234 -2.698743756 -3.093298844 -2.450976501
##  [46] -3.072896943 -2.731964518 -2.455086462 -2.726619458 -2.707499806
##  [51] -4.100456388 -2.638178127 -4.151768531 -2.636080772 -3.234950603
##  [56]  0.259417721  2.061316479  3.360829442  1.924257500  0.351056582
##  [61] -0.439651089  0.630453485  0.575879446  2.066942315  1.541814747
##  [66]  1.353961327  2.226880830  1.322451768  1.920482446  0.349058555
##  [71] -0.382164105 -1.942643033 -1.365932081 -3.294324297 -2.646728416
##  [76] -5.019472758 -3.407163423 -3.289871586 -1.321954236 -1.833741547
##  [81] -0.075060045  0.289937643  1.091136540  1.656601666  1.588655587
##  [86]  1.673385086  1.457203489  1.985718626  1.777433739  2.910512630
##  [91]  1.930150969  2.391668666  2.629108962  3.247777312  1.646782243
##  [96]  0.981641329 -0.387845345 -0.408292527 -0.394361577  0.213996083
## [101] -0.685817434 -1.263063053 -1.917841866 -1.444956484 -0.497568809
## [106] -0.033447247  1.121881124 -0.368006726  0.485066361 -1.146717660
## [111] -1.597683770 -2.655409517 -2.730587842 -2.565295420 -1.176772962
## [116]  0.493047339  2.944612004  3.482039418  3.347390470  2.821446647
## [121]  2.222582064  0.678805409  0.840980437 -0.412408916  1.297505858
## [126]  1.442460908  1.053178826  1.324269554  2.255511782  3.446367710
## [131]  3.602414218  2.353688783  0.626838624 -0.644619650 -1.277228849
## [136] -1.858172240 -0.897637373 -0.008110391 -0.057339471  1.215722917
## [141] -0.674222523 -2.263601330 -2.687454243 -4.832058211 -4.238995867
## [146] -2.661166949 -0.920250436  0.630351540 -0.337085784 -1.663003559
## [151]  0.186790802 -0.538029591 -0.463215192  0.159797910 -0.738545921
## [156]  1.678833502 -0.201894774  0.510011511 -0.133834183 -1.553101300
## [161] -0.843158383 -1.156685349  0.082587494  1.140769142  1.271545581
## [166]  1.854077573  1.075800614  0.728056225  0.328249722 -0.807124910
## [171] -1.137631584 -0.627867931 -0.652779433  1.059452434  0.746196301
## [176]  2.422382863  1.802034422  1.672267834  2.116555846  1.639096991
## [181]  4.126291100  5.148917753  6.409725416  3.881566496  3.011667002
## [186]  1.005454135  1.932200796  1.446764402  3.122257632  1.919064847
## [191]  2.829125585  0.273703906  0.307688639 -1.080306082  0.415768652
## [196]  1.428750222  1.739166315  1.582369254  2.404768267  2.249346234
## [201]  2.647025218  2.057869892 -1.353455745 -2.507538908 -2.900785852
## [206] -3.468545724 -0.556935093 -0.926333456  1.361653134  2.088601996
## [211]  1.708063501  3.316036930  2.588906900  4.950804794  4.036501510
## [216]  5.042538860  5.302442508  5.467537908  5.877358781  3.924101554
## [221]  3.434284960  2.686806969  1.776839002  1.083100658 -0.073913294
## [226] -1.683385394 -1.308345659 -1.834216649 -2.345816082 -0.721986320
## [231] -0.449487332  1.255870901  1.268575302  3.114604817  3.165662975
## [236]  3.841602445  4.379739419  2.999812402  1.837275159  0.701237447
## [241]  0.133691037  1.842992270  0.362539734  1.087594601  0.717518714
## [246]  0.374669655 -0.703143505 -0.481758719 -0.093042176 -0.291442814
## [251] -0.066413242  0.762557202  0.409863167  1.685521684 -0.926760546
## [256] -0.449729660 -0.506633618 -0.249521994  0.336737189 -1.185363545
## [261]  0.337884840 -0.017303753  1.474189013  1.584736209  2.192268736
## [266]  2.031851818  0.573490797  0.869421479  2.463621078  3.690431038
## [271]  3.481847021  2.454746322  1.802313329  1.295893239  1.887316275
## [276]  0.132998601 -0.525612343 -2.476469741 -1.938013428 -1.879802127
## [281]  0.010926286  1.300872636  1.383276411  0.044306519 -0.693773719
## [286] -1.496175422 -1.453749265 -2.252398976 -0.040152740 -1.068175607
## [291] -0.025874974 -2.379254242 -1.857437530 -1.702080094 -0.834194184
## [296]  2.831390626  1.943329467  3.385280112  1.976098970  0.569419977

Buat plot time series, plot ACF, plot PACF dan plot EACF. Idenifikasi

apakah data tersebut stasioner

Plot Time Series

plot(Y, main = "ARMA(2,2) Time Series", ylab = "Yt", xlab = "Time")

Plot ACF

acf(Y, main = "ACF of ARMA(2,2)")

Plot PACF

pacf(Y, main = "PACF of ARMA(2,2)")

Plot EACF (gunakan paket TSA)

library(TSA)
eacf(Y)
## AR/MA
##   0 1 2 3 4 5 6 7 8 9 10 11 12 13
## 0 x x o x o o o o o o o  o  o  o 
## 1 x x o o o o o o o o o  o  o  o 
## 2 o x o o o o o o o o o  o  o  o 
## 3 o x o o o o o o o o o  o  o  o 
## 4 o x x o o o o o o o o  o  o  o 
## 5 o x o o x x o o o o o  o  o  o 
## 6 o o x x x x o o o o o  o  o  o 
## 7 x o x x x x o o o o o  o  o  o

Identifikasi Stasioneritas

library(tseries)
## Warning: package 'tseries' was built under R version 4.3.2
## Registered S3 method overwritten by 'quantmod':
##   method            from
##   as.zoo.data.frame zoo
adf.test(Y)
## Warning in adf.test(Y): p-value smaller than printed p-value
## 
##  Augmented Dickey-Fuller Test
## 
## data:  Y
## Dickey-Fuller = -8.5259, Lag order = 6, p-value = 0.01
## alternative hypothesis: stationary

Buat scatterplot antara 𝑌𝑡 dengan 𝑌𝑡−1, 𝑌𝑡 dengan 𝑌𝑡−2 serta 𝑌𝑡dengan 𝑌𝑡−3

Scatterplot Yt dengan Yt-1

plot(Y[2:300], Y[1:299], main = "Scatterplot Yt vs Yt-1", xlab = "Yt-1", ylab = "Yt")

Scatterplot Yt dengan Yt-2

plot(Y[3:300], Y[1:298], main = "Scatterplot Yt vs Yt-2", xlab = "Yt-2", ylab = "Yt")

Scatterplot Yt dengan Yt-3

plot(Y[4:300], Y[1:297], main = "Scatterplot Yt vs Yt-3", xlab = "Yt-3", ylab = "Yt")

Hitung autokorelasi masing masing baik dari data bangkitan maupun secara teoritis

acf(Y)