Resampling Method

pertama kita menginstall package ISLR

library(ISLR)
## Warning: package 'ISLR' was built under R version 4.3.2
data <- ISLR::Portfolio
attach(data)
data
##               X           Y
## 1   -0.89525089 -0.23492353
## 2   -1.56245433 -0.88517599
## 3   -0.41708988  0.27188802
## 4    1.04435573 -0.73419750
## 5   -0.31556841  0.84198343
## 6   -1.73712385 -2.03719104
## 7    1.96641316  1.45295666
## 8    2.15286790 -0.43413863
## 9   -0.08120803  1.45080850
## 10  -0.89178179  0.82101623
## 11  -0.29320170 -1.04239112
## 12   0.50577917  0.60847783
## 13   0.52675125 -0.22249334
## 14   1.06646932  1.23135668
## 15   0.29401590  0.62858948
## 16   0.04254930 -1.26757362
## 17   1.83096958 -0.57275161
## 18  -0.32693750 -0.48747247
## 19   0.52148042  2.56598529
## 20   1.39986835 -0.35783613
## 21  -0.64544760 -1.41243139
## 22  -0.90435188 -0.56830479
## 23  -1.76458607 -0.74627256
## 24  -1.81048464  0.49374736
## 25  -1.16989891 -2.72528149
## 26  -0.68537574 -0.45761573
## 27   1.09091803  0.01449451
## 28  -0.43234011 -0.39983102
## 29   0.26881478 -0.20160835
## 30  -0.85184075 -1.74182929
## 31  -1.49708417 -0.82603333
## 32   0.08877475 -0.88736071
## 33  -1.60172431 -0.69529905
## 34  -1.24685724 -1.52958488
## 35  -1.06298913 -0.11063745
## 36  -0.26628306  0.04516347
## 37   1.67658383  2.52005288
## 38   0.11957257  0.53554278
## 39  -0.08600799  1.36359583
## 40   0.36808029  1.72937251
## 41  -0.27149421  1.37926733
## 42  -0.08592646 -0.12766257
## 43  -0.19075015 -0.46133336
## 44  -0.78167977  1.02239788
## 45   0.79243635 -0.81429809
## 46  -0.28286989 -1.03846881
## 47  -0.23662553  0.92845055
## 48   1.17183009  1.72983145
## 49   0.49694277 -0.92513983
## 50  -0.88737098 -2.28349796
## 51  -1.30695316 -2.38160058
## 52  -2.43276412 -2.02554559
## 53  -0.40718896 -0.33509864
## 54  -0.28566530 -1.30878131
## 55   1.52221488  1.20100315
## 56  -0.99810691 -0.94626890
## 57  -0.28997373  0.20625658
## 58  -1.23683924 -0.67544751
## 59  -0.35950696 -2.70015447
## 60   0.54355915  0.42254755
## 61  -0.40364728 -0.05438992
## 62   1.30330893  1.32896747
## 63  -0.71711724  1.33137980
## 64  -1.01270788 -0.92476923
## 65   0.83199290  2.24774587
## 66   1.33764360  0.86825646
## 67   0.60169351 -0.19821756
## 68   1.30285098  1.10466638
## 69  -0.88170058 -1.54068479
## 70  -0.82452907 -1.33700788
## 71  -0.98435652 -1.13916027
## 72  -1.38499151  0.70269993
## 73  -0.35884256 -1.69451277
## 74  -0.22661823  0.80193855
## 75  -0.94107744 -0.73318871
## 76   2.46033595 -0.04837282
## 77   0.71679728  0.60233676
## 78  -0.24808702 -1.01849037
## 79   1.01077289  0.05297802
## 80   2.31304863  1.75235888
## 81   0.83517980  0.98571488
## 82  -1.07190334 -1.24729787
## 83  -1.65052614  0.21546453
## 84  -0.60048569 -0.42094053
## 85  -0.05852938  0.12762087
## 86   0.07572674 -0.52214922
## 87  -1.15783156  0.59089374
## 88   1.67360609  0.11462332
## 89  -1.04398824 -0.41894428
## 90   0.01468748 -0.55874662
## 91   0.67532197  1.48262979
## 92   1.77834231  0.94277411
## 93  -1.29576364 -1.08520381
## 94   0.07960202 -0.53910081
## 95   2.26085771  0.67322484
## 96   0.47909092  1.45477446
## 97  -0.53502000 -0.39917481
## 98  -0.77312933 -0.95717485
## 99   0.40363434  1.39603817
## 100 -0.58849644 -0.49728509

Menggunakan Metode Resampling Bootstrap

mencari estimasi, varians, dan standar error

  1. Membuat dataframe

    Miftah <- LETTERS[1:100]
    item1 <- X
    item2 <- Y
    DF <- data.frame(Miftah,item1,item2)
    DF
    ##     Miftah       item1       item2
    ## 1        A -0.89525089 -0.23492353
    ## 2        B -1.56245433 -0.88517599
    ## 3        C -0.41708988  0.27188802
    ## 4        D  1.04435573 -0.73419750
    ## 5        E -0.31556841  0.84198343
    ## 6        F -1.73712385 -2.03719104
    ## 7        G  1.96641316  1.45295666
    ## 8        H  2.15286790 -0.43413863
    ## 9        I -0.08120803  1.45080850
    ## 10       J -0.89178179  0.82101623
    ## 11       K -0.29320170 -1.04239112
    ## 12       L  0.50577917  0.60847783
    ## 13       M  0.52675125 -0.22249334
    ## 14       N  1.06646932  1.23135668
    ## 15       O  0.29401590  0.62858948
    ## 16       P  0.04254930 -1.26757362
    ## 17       Q  1.83096958 -0.57275161
    ## 18       R -0.32693750 -0.48747247
    ## 19       S  0.52148042  2.56598529
    ## 20       T  1.39986835 -0.35783613
    ## 21       U -0.64544760 -1.41243139
    ## 22       V -0.90435188 -0.56830479
    ## 23       W -1.76458607 -0.74627256
    ## 24       X -1.81048464  0.49374736
    ## 25       Y -1.16989891 -2.72528149
    ## 26       Z -0.68537574 -0.45761573
    ## 27    <NA>  1.09091803  0.01449451
    ## 28    <NA> -0.43234011 -0.39983102
    ## 29    <NA>  0.26881478 -0.20160835
    ## 30    <NA> -0.85184075 -1.74182929
    ## 31    <NA> -1.49708417 -0.82603333
    ## 32    <NA>  0.08877475 -0.88736071
    ## 33    <NA> -1.60172431 -0.69529905
    ## 34    <NA> -1.24685724 -1.52958488
    ## 35    <NA> -1.06298913 -0.11063745
    ## 36    <NA> -0.26628306  0.04516347
    ## 37    <NA>  1.67658383  2.52005288
    ## 38    <NA>  0.11957257  0.53554278
    ## 39    <NA> -0.08600799  1.36359583
    ## 40    <NA>  0.36808029  1.72937251
    ## 41    <NA> -0.27149421  1.37926733
    ## 42    <NA> -0.08592646 -0.12766257
    ## 43    <NA> -0.19075015 -0.46133336
    ## 44    <NA> -0.78167977  1.02239788
    ## 45    <NA>  0.79243635 -0.81429809
    ## 46    <NA> -0.28286989 -1.03846881
    ## 47    <NA> -0.23662553  0.92845055
    ## 48    <NA>  1.17183009  1.72983145
    ## 49    <NA>  0.49694277 -0.92513983
    ## 50    <NA> -0.88737098 -2.28349796
    ## 51    <NA> -1.30695316 -2.38160058
    ## 52    <NA> -2.43276412 -2.02554559
    ## 53    <NA> -0.40718896 -0.33509864
    ## 54    <NA> -0.28566530 -1.30878131
    ## 55    <NA>  1.52221488  1.20100315
    ## 56    <NA> -0.99810691 -0.94626890
    ## 57    <NA> -0.28997373  0.20625658
    ## 58    <NA> -1.23683924 -0.67544751
    ## 59    <NA> -0.35950696 -2.70015447
    ## 60    <NA>  0.54355915  0.42254755
    ## 61    <NA> -0.40364728 -0.05438992
    ## 62    <NA>  1.30330893  1.32896747
    ## 63    <NA> -0.71711724  1.33137980
    ## 64    <NA> -1.01270788 -0.92476923
    ## 65    <NA>  0.83199290  2.24774587
    ## 66    <NA>  1.33764360  0.86825646
    ## 67    <NA>  0.60169351 -0.19821756
    ## 68    <NA>  1.30285098  1.10466638
    ## 69    <NA> -0.88170058 -1.54068479
    ## 70    <NA> -0.82452907 -1.33700788
    ## 71    <NA> -0.98435652 -1.13916027
    ## 72    <NA> -1.38499151  0.70269993
    ## 73    <NA> -0.35884256 -1.69451277
    ## 74    <NA> -0.22661823  0.80193855
    ## 75    <NA> -0.94107744 -0.73318871
    ## 76    <NA>  2.46033595 -0.04837282
    ## 77    <NA>  0.71679728  0.60233676
    ## 78    <NA> -0.24808702 -1.01849037
    ## 79    <NA>  1.01077289  0.05297802
    ## 80    <NA>  2.31304863  1.75235888
    ## 81    <NA>  0.83517980  0.98571488
    ## 82    <NA> -1.07190334 -1.24729787
    ## 83    <NA> -1.65052614  0.21546453
    ## 84    <NA> -0.60048569 -0.42094053
    ## 85    <NA> -0.05852938  0.12762087
    ## 86    <NA>  0.07572674 -0.52214922
    ## 87    <NA> -1.15783156  0.59089374
    ## 88    <NA>  1.67360609  0.11462332
    ## 89    <NA> -1.04398824 -0.41894428
    ## 90    <NA>  0.01468748 -0.55874662
    ## 91    <NA>  0.67532197  1.48262979
    ## 92    <NA>  1.77834231  0.94277411
    ## 93    <NA> -1.29576364 -1.08520381
    ## 94    <NA>  0.07960202 -0.53910081
    ## 95    <NA>  2.26085771  0.67322484
    ## 96    <NA>  0.47909092  1.45477446
    ## 97    <NA> -0.53502000 -0.39917481
    ## 98    <NA> -0.77312933 -0.95717485
    ## 99    <NA>  0.40363434  1.39603817
    ## 100   <NA> -0.58849644 -0.49728509
  2. Algoritma Rstudio

    set.seed(1)
    n <- nrow(DF)
    b <- 10000
    y <- matrix(sample(DF$item1,n*b,replace = TRUE),b)
    x <- matrix(sample(DF$item2,n*b,replace = TRUE),b)
    ybar <- apply(y,1,mean)
    xbar <- apply(x,1,mean)
    teta.i <- ybar/(xbar+ybar)
    teta.b <- mean(teta.i)
    var.b <- (sum(teta.i^2)-(b*teta.b^2))/(b-1)
    se.b <- sqrt(var.b)
    BOOTS.TRAP <- matrix(c(teta.b,var.b,se.b))
    row.names(BOOTS.TRAP) <- c("ESTIMASI","VARIANS","STANDAR ERROR")
    colnames(BOOTS.TRAP) <- c("HASIL BOOTSTRAP")
    BOOTS.TRAP
    ##               HASIL BOOTSTRAP
    ## ESTIMASI            0.9272088
    ## VARIANS           552.3971070
    ## STANDAR ERROR      23.5031297

Menggunakan Metode Resampling Jackknife

mencari Estimasi, Varians, dan Standar Error

n <- nrow(DF)
teta.topi <- mean(DF$item1)/(mean(DF$item1)+mean(DF$item2))
y <- matrix(NA,n,n-1)
x <- matrix(NA,n,n-1)
for (i in 1:n) {
  y[i,] <- DF$item1[-i]
  x[i,] <- DF$item2[-i]
}
ybar <- apply(y,1,mean)
xbar <- apply(x,1,mean)
teta.i <- ybar/(xbar + ybar)
teta.jk <- n*teta.topi - (n-1)*mean(teta.i)
var.jk <- (n-1)/n*(sum(teta.i^2)-(n*mean(teta.i)^2))
se.jk <- sqrt(var.jk)
JACK.KNIFE <- matrix(c(teta.jk,var.jk,se.jk))
row.names(JACK.KNIFE) <- c("ESTIMASI","VARIANS","STANDAR ERROR")
colnames(JACK.KNIFE) <- c("HASIL JACKKNIFE")
JACK.KNIFE
##               HASIL JACKKNIFE
## ESTIMASI           0.47715352
## VARIANS            0.09622771
## STANDAR ERROR      0.31020591