IPB University

Syaza Abdu Razzaq

11/02/2022

Project 1 Pembelajaran Mesin Statistika

Pada kali ini, kita akan mensimulasikan bagaimana cara membangun model dengan metode regresi diantaranya best-subset, ridge, lasso, dan elastic-net.

Data akan digenerate dengan beberapa ketentuan tertentu untuk kemudian selanjutnya akan dilakukan ke tahap pembuatan model.

Untuk membangun model tersebut, berikut ini adalah metodologi atau algoritma yang digunakan.

  1. Import Data

  2. Pre Processing Data

  3. Generate Model

  4. Tuning Hyperparameter

  5. Prediction

Import Data

Pada case ini kita akan menggunakan data simulasi yang dibangkitkan dengan beberapa ketentuan tertentu diantaranya sbb:

Bangkitkan data sebanyak n = 10000, dengan ketentuan sebagai berikut:

  1. Bangkitkan X1, X2, …, X50 dari sebaran Normal(10, 2.k), yang mana X1 dan X2 berkorelasi sebesar 0.95, X4 dan X5 berkorelasi sebesar −0.85.

  2. Berdasarkan 10000 data yang dibangkitkan tersebut hitung korelasi X1 dan X2 serta korelasi X4 dan X5. Ini untuk mengecek bahwa simulasinya sudah benar.

  3. X51 = 3.5(X1) + μ dan X52 = −0.65(X2) + μ, sedangkan μ menyebar Normal(2, 1.k).

  4. β0 = 2.5; β1 = β2 = … = β20 = 3.5; β21 = β22 = … = β50 = 0; β51 = β52 = −4.5 .

  5. Y = β0 + β1X1 + β2X2 + … + β52X52 + ε, sedangkan ε menyebar Normal(0, 1.2k).

  6. Data Y, X1, X2, …, X52 hasil bangkitan tersebut disimpan dengan nama “DAT.SIM.01”.

library(rpart)
library(pROC)
## Type 'citation("pROC")' for a citation.
## 
## Attaching package: 'pROC'
## The following objects are masked from 'package:stats':
## 
##     cov, smooth, var
library(tidyverse)
## -- Attaching packages --------------------------------------- tidyverse 1.3.1 --
## v ggplot2 3.3.5     v purrr   0.3.4
## v tibble  3.1.3     v dplyr   1.0.7
## v tidyr   1.1.3     v stringr 1.4.0
## v readr   2.0.1     v forcats 0.5.1
## -- Conflicts ------------------------------------------ tidyverse_conflicts() --
## x dplyr::filter() masks stats::filter()
## x dplyr::lag()    masks stats::lag()
library(mlr3verse)
## Loading required package: mlr3
library(mlr3extralearners)
## 
## Attaching package: 'mlr3extralearners'
## The following objects are masked from 'package:mlr3':
## 
##     lrn, lrns
library(precrec)
## 
## Attaching package: 'precrec'
## The following object is masked from 'package:pROC':
## 
##     auc
library(adabag)
## Loading required package: caret
## Loading required package: lattice
## 
## Attaching package: 'caret'
## The following object is masked from 'package:purrr':
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##     lift
## Loading required package: foreach
## 
## Attaching package: 'foreach'
## The following objects are masked from 'package:purrr':
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##     accumulate, when
## Loading required package: doParallel
## Loading required package: iterators
## Loading required package: parallel
library(ROCR)
library(ROCit)
library(magrittr)
## 
## Attaching package: 'magrittr'
## The following object is masked from 'package:purrr':
## 
##     set_names
## The following object is masked from 'package:tidyr':
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##     extract
library(visdat)
library(naniar)
library(UpSetR)
## 
## Attaching package: 'UpSetR'
## The following object is masked from 'package:lattice':
## 
##     histogram
library(laeken)
library(vcd)
## Loading required package: grid
library(VIM)
## Loading required package: colorspace
## 
## Attaching package: 'colorspace'
## The following object is masked from 'package:pROC':
## 
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## VIM is ready to use.
## Suggestions and bug-reports can be submitted at: https://github.com/statistikat/VIM/issues
## 
## Attaching package: 'VIM'
## The following object is masked from 'package:datasets':
## 
##     sleep
library(sm)
## Package 'sm', version 2.2-5.7: type help(sm) for summary information
library(ggplot2)
library(dplyr)
library(mlbench)
library(caret)
library(mlr3verse)
library(mlr3fselect)
library(DataExplorer)
library(skimr)
## 
## Attaching package: 'skimr'
## The following object is masked from 'package:naniar':
## 
##     n_complete
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library(corrplot)
## corrplot 0.92 loaded
library(leaps)
library(olsrr)
## 
## Attaching package: 'olsrr'
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##     rivers
library(kableExtra) #Tampilan Tabel
## 
## Attaching package: 'kableExtra'
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## 
##     group_rows
library(agricolae)  #Pemeriksaan Asumsi
library(lmtest)     #Untuk pengecekan asumsi
## Loading required package: zoo
## 
## Attaching package: 'zoo'
## The following objects are masked from 'package:base':
## 
##     as.Date, as.Date.numeric
library(car)        #Untuk pengecekan asumsi
## Loading required package: carData
## 
## Attaching package: 'car'
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##     recode
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##     some
library(tseries)    #Untuk pengecekan asumsi
## Registered S3 method overwritten by 'quantmod':
##   method            from
##   as.zoo.data.frame zoo
library(glmnet)
## Loading required package: Matrix
## 
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## The following objects are masked from 'package:tidyr':
## 
##     expand, pack, unpack
## Loaded glmnet 4.1-2
library(glmnetUtils)
## 
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## The following objects are masked from 'package:glmnet':
## 
##     cv.glmnet, glmnet
library(broom)
library(ggpubr)
library(modelr)
## 
## Attaching package: 'modelr'
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##     bootstrap
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library(precrec)
library(adabag)
library(rpart.plot)



k <- 7
sigmaX<- 2.7
meanX <- 10
jumlah<-10000

set.seed(10)
dataX <- replicate(50,rnorm(jumlah,mean=meanX,sd= sigmaX))
dataX<-as.data.frame(dataX)

correlatedValue = function(x, r){
  r2 = r**2
  ve = 1-r2
  SD = sqrt(ve)
  e  = rnorm(length(x), mean=0, sd=SD)
  y  = r*x + e
  return(y)
}

set.seed(043)
X1 = rnorm(10000, 10, 2.7)
X2 = correlatedValue(x=X1, r=.7480)

cor(X1,X2)
## [1] 0.9500737
set.seed(0431)
X4 = rnorm(10000, 10, 2.7)
X5 = correlatedValue(x=X4, r=-(0.519))
cor(X4,X5)
## [1] -0.8575801
#soal nomor 3
set.seed(0432)
miu<- rnorm(jumlah,2,1.7)
V51<-X1*3.5 + miu
V52<-X2*(-0.65)+miu

#soal nomor 4
dataX$V1<- X1
dataX$V2<-X2

dataX<- cbind(dataX,V51,V52)
dim(dataX)
## [1] 10000    52
head(dataX)
class(dataX)
## [1] "data.frame"
dataX$V1<- as.integer(dataX$V1)
dataX$V2<- as.integer(dataX$V2)
dataX$V3<- as.integer(dataX$V3)
dataX$V4<- as.integer(dataX$V4)
dataX$V5<- as.integer(dataX$V5)
dataX$V6<- as.integer(dataX$V6)
dataX$V7<- as.integer(dataX$V7)
dataX$V8<- as.integer(dataX$V8)
dataX$V9<- as.integer(dataX$V9)
dataX$V10<- as.integer(dataX$V10)
dataX$V11<- as.integer(dataX$V11)
dataX$V12<- as.integer(dataX$V12)
dataX$V13<- as.integer(dataX$V13)
dataX$V14<- as.integer(dataX$V14)
dataX$V15<- as.integer(dataX$V15)
dataX$V16<- as.integer(dataX$V16)
dataX$V17<- as.integer(dataX$V17)
dataX$V18<- as.integer(dataX$V18)
dataX$V19<- as.integer(dataX$V19)
dataX$V20<- as.integer(dataX$V20)
dataX$V21<- as.integer(dataX$V21)
dataX$V22<- as.integer(dataX$V22)
dataX$V23<- as.integer(dataX$V23)
dataX$V24<- as.integer(dataX$V24)
dataX$V25<- as.integer(dataX$V25)
dataX$V26<- as.integer(dataX$V26)
dataX$V27<- as.integer(dataX$V27)
dataX$V28<- as.integer(dataX$V28)
dataX$V29<- as.integer(dataX$V29)
dataX$V30<- as.integer(dataX$V30)
dataX$V31<- as.integer(dataX$V31)
dataX$V32<- as.integer(dataX$V32)
dataX$V33<- as.integer(dataX$V33)
dataX$V34<- as.integer(dataX$V34)
dataX$V35<- as.integer(dataX$V35)
dataX$V36<- as.integer(dataX$V36)
dataX$V37<- as.integer(dataX$V37)
dataX$V38<- as.integer(dataX$V38)
dataX$V39<- as.integer(dataX$V39)
dataX$V40<- as.integer(dataX$V40)
dataX$V41<- as.integer(dataX$V41)
dataX$V42<- as.integer(dataX$V42)
dataX$V43<- as.integer(dataX$V43)
dataX$V44<- as.integer(dataX$V44)
dataX$V45<- as.integer(dataX$V45)
dataX$V46<- as.integer(dataX$V46)
dataX$V47<- as.integer(dataX$V47)
dataX$V48<- as.integer(dataX$V48)
dataX$V49<- as.integer(dataX$V49)
dataX$V50<- as.integer(dataX$V50)
dataX$V51<- as.integer(dataX$V51)
dataX$V52<- as.integer(dataX$V52)

dim(dataX)
## [1] 10000    52
glimpse(dataX)
## Rows: 10,000
## Columns: 52
## $ V1  <int> 9, 5, 8, 11, 7, 9, 11, 9, 8, 4, 14, 7, 9, 12, 11, 15, 13, 5, 10, 8~
## $ V2  <int> 6, 5, 6, 7, 5, 6, 7, 8, 5, 3, 11, 6, 7, 9, 7, 10, 8, 4, 7, 6, 6, 8~
## $ V3  <int> 12, 9, 14, 11, 7, 5, 17, 4, 5, 8, 16, 12, 16, 13, 13, 8, 12, 10, 9~
## $ V4  <int> 7, 9, 6, 14, 13, 14, 10, 6, 8, 9, 5, 4, 12, 6, 7, 14, 11, 13, 7, 1~
## $ V5  <int> 14, 7, 3, 8, 16, 9, 12, 7, 7, 13, 9, 4, 7, 7, 6, 11, 9, 9, 7, 6, 1~
## $ V6  <int> 14, 15, 11, 7, 11, 6, 6, 6, 8, 12, 10, 9, 11, 5, 9, 11, 15, 6, 10,~
## $ V7  <int> 11, 10, 13, 10, 8, 13, 7, 7, 7, 12, 13, 12, 10, 11, 3, 12, 14, 14,~
## $ V8  <int> 9, 10, 9, 6, 7, 11, 7, 3, 5, 5, 8, 10, 11, 8, 8, 9, 10, 11, 8, 10,~
## $ V9  <int> 12, 9, 8, 9, 8, 10, 12, 5, 7, 9, 8, 7, 11, 1, 10, 7, 5, 10, 9, 8, ~
## $ V10 <int> 14, 12, 17, 8, 13, 9, 14, 6, 11, 14, 4, 13, 7, 13, 12, 10, 7, 11, ~
## $ V11 <int> 10, 10, 12, 7, 10, 10, 7, 13, 7, 12, 9, 11, 8, 11, 8, 13, 0, 9, 10~
## $ V12 <int> 12, 12, 5, 15, 0, 10, 9, 7, 15, 11, 8, 9, 8, 9, 10, 9, 11, 12, 12,~
## $ V13 <int> 6, 14, 6, 8, 6, 10, 8, 10, 8, 8, 11, 7, 12, 14, 9, 6, 11, 9, 6, 9,~
## $ V14 <int> 10, 8, 8, 10, 14, 8, 5, 8, 9, 6, 12, 9, 11, 10, 13, 12, 12, 13, 12~
## $ V15 <int> 10, 12, 12, 11, 5, 4, 10, 13, 6, 10, 9, 4, 12, 15, 16, 10, 11, 11,~
## $ V16 <int> 9, 8, 8, 12, 12, 8, 11, 5, 10, 13, 13, 12, 7, 6, 14, 4, 13, 8, 14,~
## $ V17 <int> 12, 4, 10, 12, 7, 4, 9, 11, 13, 8, 10, 10, 9, 12, 13, 9, 8, 7, 7, ~
## $ V18 <int> 8, 10, 6, 9, 13, 9, 8, 8, 8, 9, 13, 8, 10, 11, 12, 8, 13, 11, 10, ~
## $ V19 <int> 14, 11, 8, 10, 12, 3, 9, 10, 16, 9, 9, 10, 11, 7, 9, 11, 11, 12, 9~
## $ V20 <int> 9, 9, 12, 7, 9, 9, 11, 12, 7, 9, 11, 3, 11, 6, 4, 10, 9, 9, 12, 6,~
## $ V21 <int> 10, 6, 7, 5, 13, 10, 7, 11, 7, 9, 10, 13, 12, 12, 7, 5, 7, 6, 9, 1~
## $ V22 <int> 13, 11, 6, 4, 13, 7, 10, 9, 12, 10, 6, 13, 7, 13, 10, 5, 11, 11, 1~
## $ V23 <int> 10, 9, 11, 8, 9, 4, 6, 12, 16, 6, 10, 11, 10, 4, 8, 8, 10, 9, 7, 6~
## $ V24 <int> 14, 11, 7, 11, 7, 12, 8, 8, 11, 6, 6, 7, 12, 11, 8, 10, 8, 7, 9, 8~
## $ V25 <int> 9, 11, 9, 9, 11, 11, 10, 15, 5, 9, 11, 9, 12, 8, 10, 9, 13, 13, 13~
## $ V26 <int> 7, 12, 7, 10, 9, 9, 5, 5, 11, 11, 11, 9, 15, 10, 5, 6, 10, 6, 10, ~
## $ V27 <int> 9, 9, 14, 9, 8, 6, 6, 13, 10, 12, 10, 9, 9, 9, 11, 10, 9, 12, 10, ~
## $ V28 <int> 13, 15, 10, 12, 11, 13, 10, 7, 8, 9, 8, 11, 11, 6, 7, 13, 13, 10, ~
## $ V29 <int> 13, 11, 11, 13, 13, 10, 11, 10, 11, 7, 12, 11, 10, 10, 8, 8, 8, 6,~
## $ V30 <int> 12, 9, 5, 7, 9, 12, 6, 8, 8, 9, 6, 10, 13, 8, 9, 4, 8, 9, 11, 11, ~
## $ V31 <int> 8, 7, 10, 9, 9, 11, 9, 12, 10, 7, 13, 11, 10, 9, 8, 14, 9, 13, 16,~
## $ V32 <int> 10, 10, 8, 8, 4, 8, 11, 10, 11, 10, 8, 10, 6, 7, 6, 7, 11, 9, 2, 5~
## $ V33 <int> 8, 6, 9, 8, 8, 9, 11, 11, 6, 9, 9, 13, 5, 10, 10, 11, 9, 13, 9, 11~
## $ V34 <int> 9, 12, 11, 13, 11, 10, 6, 9, 10, 9, 15, 7, 10, 10, 10, 8, 4, 12, 1~
## $ V35 <int> 7, 11, 14, 6, 13, 6, 7, 10, 9, 6, 11, 7, 10, 8, 6, 9, 7, 10, 10, 8~
## $ V36 <int> 13, 9, 8, 11, 9, 11, 8, 9, 10, 13, 12, 15, 17, 10, 9, 10, 9, 13, 1~
## $ V37 <int> 11, 3, 8, 11, 10, 10, 11, 13, 13, 7, 13, 4, 11, 8, 11, 6, 16, 6, 9~
## $ V38 <int> 5, 8, 9, 14, 14, 10, 7, 11, 11, 12, 8, 14, 11, 10, 12, 10, 10, 12,~
## $ V39 <int> 9, 5, 8, 12, 13, 9, 10, 8, 10, 10, 11, 13, 14, 10, 11, 8, 5, 5, 5,~
## $ V40 <int> 12, 11, 6, 7, 9, 11, 8, 7, 8, 12, 11, 10, 3, 8, 9, 9, 9, 11, 7, 12~
## $ V41 <int> 11, 11, 7, 13, 14, 7, 9, 6, 10, 10, 12, 11, 7, 7, 6, 9, 9, 6, 10, ~
## $ V42 <int> 7, 9, 11, 12, 6, 15, 8, 9, 9, 7, 14, 8, 7, 11, 8, 8, 7, 16, 6, 10,~
## $ V43 <int> 7, 12, 11, 11, 8, 10, 10, 7, 11, 10, 13, 8, 5, 10, 9, 10, 8, 11, 1~
## $ V44 <int> 11, 11, 12, 10, 8, 10, 11, 9, 8, 15, 9, 13, 10, 10, 11, 11, 11, 10~
## $ V45 <int> 10, 10, 13, 8, 7, 6, 12, 10, 11, 10, 7, 14, 8, 7, 9, 7, 11, 8, 8, ~
## $ V46 <int> 10, 9, 7, 8, 8, 14, 9, 11, 10, 7, 7, 13, 8, 9, 4, 10, 8, 12, 11, 1~
## $ V47 <int> 9, 9, 11, 12, 9, 7, 7, 13, 12, 9, 10, 7, 8, 15, 6, 10, 7, 8, 6, 8,~
## $ V48 <int> 9, 8, 9, 12, 9, 11, 11, 11, 11, 8, 6, 9, 9, 8, 6, 6, 12, 7, 14, 10~
## $ V49 <int> 7, 5, 12, 8, 13, 9, 13, 9, 10, 14, 3, 5, 5, 7, 8, 8, 10, 10, 11, 1~
## $ V50 <int> 12, 5, 7, 8, 7, 13, 12, 10, 7, 7, 12, 5, 8, 8, 7, 13, 9, 13, 10, 9~
## $ V51 <int> 35, 24, 33, 42, 29, 35, 39, 35, 30, 18, 53, 28, 32, 45, 44, 53, 51~
## $ V52 <int> -3, 0, -1, -1, 0, -1, -3, -4, -1, 0, -5, -1, -3, -5, -1, -7, -2, -~
#Soal nomor 4
set.seed(0435)
epsilon<- rnorm(jumlah, 0, 1.27)
epsilon<-as.integer(epsilon)
Y<- 2.5 + 3.5*dataX$V1+ 3.5*dataX$V2 + 3.5*dataX$V3 + 3.5*dataX$V4 + 3.5*dataX$V5 + 3.5*dataX$V6 + 3.5*dataX$V7 + 3.5*dataX$V8 + 3.5*dataX$V9 + 3.5*dataX$V10 + 3.5*dataX$V11 + 3.5*dataX$V12 + 3.5*dataX$V13 + 3.5*dataX$V14 + 3.5*dataX$V15 + 3.5*dataX$V16 + 3.5*dataX$V17 + 3.5*dataX$V18 + 3.5*dataX$V19 + 3.5*dataX$V20 - 4.5*dataX$V51 - 4.5*dataX$V52 + epsilon
Y<-as.integer(Y)
dataX<- cbind(Y, dataX)

DAT.SIM.01<- dataX
dim(DAT.SIM.01)
## [1] 10000    53
head(DAT.SIM.01)
glimpse(DAT.SIM.01)
## Rows: 10,000
## Columns: 53
## $ Y   <int> 587, 556, 495, 491, 512, 434, 505, 416, 467, 565, 497, 466, 572, 4~
## $ V1  <int> 9, 5, 8, 11, 7, 9, 11, 9, 8, 4, 14, 7, 9, 12, 11, 15, 13, 5, 10, 8~
## $ V2  <int> 6, 5, 6, 7, 5, 6, 7, 8, 5, 3, 11, 6, 7, 9, 7, 10, 8, 4, 7, 6, 6, 8~
## $ V3  <int> 12, 9, 14, 11, 7, 5, 17, 4, 5, 8, 16, 12, 16, 13, 13, 8, 12, 10, 9~
## $ V4  <int> 7, 9, 6, 14, 13, 14, 10, 6, 8, 9, 5, 4, 12, 6, 7, 14, 11, 13, 7, 1~
## $ V5  <int> 14, 7, 3, 8, 16, 9, 12, 7, 7, 13, 9, 4, 7, 7, 6, 11, 9, 9, 7, 6, 1~
## $ V6  <int> 14, 15, 11, 7, 11, 6, 6, 6, 8, 12, 10, 9, 11, 5, 9, 11, 15, 6, 10,~
## $ V7  <int> 11, 10, 13, 10, 8, 13, 7, 7, 7, 12, 13, 12, 10, 11, 3, 12, 14, 14,~
## $ V8  <int> 9, 10, 9, 6, 7, 11, 7, 3, 5, 5, 8, 10, 11, 8, 8, 9, 10, 11, 8, 10,~
## $ V9  <int> 12, 9, 8, 9, 8, 10, 12, 5, 7, 9, 8, 7, 11, 1, 10, 7, 5, 10, 9, 8, ~
## $ V10 <int> 14, 12, 17, 8, 13, 9, 14, 6, 11, 14, 4, 13, 7, 13, 12, 10, 7, 11, ~
## $ V11 <int> 10, 10, 12, 7, 10, 10, 7, 13, 7, 12, 9, 11, 8, 11, 8, 13, 0, 9, 10~
## $ V12 <int> 12, 12, 5, 15, 0, 10, 9, 7, 15, 11, 8, 9, 8, 9, 10, 9, 11, 12, 12,~
## $ V13 <int> 6, 14, 6, 8, 6, 10, 8, 10, 8, 8, 11, 7, 12, 14, 9, 6, 11, 9, 6, 9,~
## $ V14 <int> 10, 8, 8, 10, 14, 8, 5, 8, 9, 6, 12, 9, 11, 10, 13, 12, 12, 13, 12~
## $ V15 <int> 10, 12, 12, 11, 5, 4, 10, 13, 6, 10, 9, 4, 12, 15, 16, 10, 11, 11,~
## $ V16 <int> 9, 8, 8, 12, 12, 8, 11, 5, 10, 13, 13, 12, 7, 6, 14, 4, 13, 8, 14,~
## $ V17 <int> 12, 4, 10, 12, 7, 4, 9, 11, 13, 8, 10, 10, 9, 12, 13, 9, 8, 7, 7, ~
## $ V18 <int> 8, 10, 6, 9, 13, 9, 8, 8, 8, 9, 13, 8, 10, 11, 12, 8, 13, 11, 10, ~
## $ V19 <int> 14, 11, 8, 10, 12, 3, 9, 10, 16, 9, 9, 10, 11, 7, 9, 11, 11, 12, 9~
## $ V20 <int> 9, 9, 12, 7, 9, 9, 11, 12, 7, 9, 11, 3, 11, 6, 4, 10, 9, 9, 12, 6,~
## $ V21 <int> 10, 6, 7, 5, 13, 10, 7, 11, 7, 9, 10, 13, 12, 12, 7, 5, 7, 6, 9, 1~
## $ V22 <int> 13, 11, 6, 4, 13, 7, 10, 9, 12, 10, 6, 13, 7, 13, 10, 5, 11, 11, 1~
## $ V23 <int> 10, 9, 11, 8, 9, 4, 6, 12, 16, 6, 10, 11, 10, 4, 8, 8, 10, 9, 7, 6~
## $ V24 <int> 14, 11, 7, 11, 7, 12, 8, 8, 11, 6, 6, 7, 12, 11, 8, 10, 8, 7, 9, 8~
## $ V25 <int> 9, 11, 9, 9, 11, 11, 10, 15, 5, 9, 11, 9, 12, 8, 10, 9, 13, 13, 13~
## $ V26 <int> 7, 12, 7, 10, 9, 9, 5, 5, 11, 11, 11, 9, 15, 10, 5, 6, 10, 6, 10, ~
## $ V27 <int> 9, 9, 14, 9, 8, 6, 6, 13, 10, 12, 10, 9, 9, 9, 11, 10, 9, 12, 10, ~
## $ V28 <int> 13, 15, 10, 12, 11, 13, 10, 7, 8, 9, 8, 11, 11, 6, 7, 13, 13, 10, ~
## $ V29 <int> 13, 11, 11, 13, 13, 10, 11, 10, 11, 7, 12, 11, 10, 10, 8, 8, 8, 6,~
## $ V30 <int> 12, 9, 5, 7, 9, 12, 6, 8, 8, 9, 6, 10, 13, 8, 9, 4, 8, 9, 11, 11, ~
## $ V31 <int> 8, 7, 10, 9, 9, 11, 9, 12, 10, 7, 13, 11, 10, 9, 8, 14, 9, 13, 16,~
## $ V32 <int> 10, 10, 8, 8, 4, 8, 11, 10, 11, 10, 8, 10, 6, 7, 6, 7, 11, 9, 2, 5~
## $ V33 <int> 8, 6, 9, 8, 8, 9, 11, 11, 6, 9, 9, 13, 5, 10, 10, 11, 9, 13, 9, 11~
## $ V34 <int> 9, 12, 11, 13, 11, 10, 6, 9, 10, 9, 15, 7, 10, 10, 10, 8, 4, 12, 1~
## $ V35 <int> 7, 11, 14, 6, 13, 6, 7, 10, 9, 6, 11, 7, 10, 8, 6, 9, 7, 10, 10, 8~
## $ V36 <int> 13, 9, 8, 11, 9, 11, 8, 9, 10, 13, 12, 15, 17, 10, 9, 10, 9, 13, 1~
## $ V37 <int> 11, 3, 8, 11, 10, 10, 11, 13, 13, 7, 13, 4, 11, 8, 11, 6, 16, 6, 9~
## $ V38 <int> 5, 8, 9, 14, 14, 10, 7, 11, 11, 12, 8, 14, 11, 10, 12, 10, 10, 12,~
## $ V39 <int> 9, 5, 8, 12, 13, 9, 10, 8, 10, 10, 11, 13, 14, 10, 11, 8, 5, 5, 5,~
## $ V40 <int> 12, 11, 6, 7, 9, 11, 8, 7, 8, 12, 11, 10, 3, 8, 9, 9, 9, 11, 7, 12~
## $ V41 <int> 11, 11, 7, 13, 14, 7, 9, 6, 10, 10, 12, 11, 7, 7, 6, 9, 9, 6, 10, ~
## $ V42 <int> 7, 9, 11, 12, 6, 15, 8, 9, 9, 7, 14, 8, 7, 11, 8, 8, 7, 16, 6, 10,~
## $ V43 <int> 7, 12, 11, 11, 8, 10, 10, 7, 11, 10, 13, 8, 5, 10, 9, 10, 8, 11, 1~
## $ V44 <int> 11, 11, 12, 10, 8, 10, 11, 9, 8, 15, 9, 13, 10, 10, 11, 11, 11, 10~
## $ V45 <int> 10, 10, 13, 8, 7, 6, 12, 10, 11, 10, 7, 14, 8, 7, 9, 7, 11, 8, 8, ~
## $ V46 <int> 10, 9, 7, 8, 8, 14, 9, 11, 10, 7, 7, 13, 8, 9, 4, 10, 8, 12, 11, 1~
## $ V47 <int> 9, 9, 11, 12, 9, 7, 7, 13, 12, 9, 10, 7, 8, 15, 6, 10, 7, 8, 6, 8,~
## $ V48 <int> 9, 8, 9, 12, 9, 11, 11, 11, 11, 8, 6, 9, 9, 8, 6, 6, 12, 7, 14, 10~
## $ V49 <int> 7, 5, 12, 8, 13, 9, 13, 9, 10, 14, 3, 5, 5, 7, 8, 8, 10, 10, 11, 1~
## $ V50 <int> 12, 5, 7, 8, 7, 13, 12, 10, 7, 7, 12, 5, 8, 8, 7, 13, 9, 13, 10, 9~
## $ V51 <int> 35, 24, 33, 42, 29, 35, 39, 35, 30, 18, 53, 28, 32, 45, 44, 53, 51~
## $ V52 <int> -3, 0, -1, -1, 0, -1, -3, -4, -1, 0, -5, -1, -3, -5, -1, -7, -2, -~

Pre-Processing Data

Sebelum dilakukan pembuatan model, terlebih dahulu dilakukan splitting data dan pengecekan data sebagai berikut.

Split Data

Data tersebut akan kita bagi dua yaitu data training dan data test, data training adalah data yang nantinya akan digunakan untuk membangun model, sedangkan data test akan digunakan utuk mengukur akurasi model yang sudah dibuat. Data test dan data training akan dibagi dengan proporsi 20%:80%.

set.seed(1238)
index <- createDataPartition(DAT.SIM.01$Y , p = 0.8,list = FALSE)

#membagi data menjadi data train dan data test
train.dataindex <- DAT.SIM.01[index,]
dim(train.dataindex)
## [1] 8002   53
test.dataindex <- DAT.SIM.01[-index,]
dim(test.dataindex)
## [1] 1998   53

Variabel respon

Melihat sebaran variabel respon apakah sudah berdistribusi normal.

#Cek Normalitas variabel respon
ggpubr::gghistogram(data = train.dataindex, x = "Y",fill = "darkgreen")+scale_y_continuous(expand = c(0,0))
## Warning: Using `bins = 30` by default. Pick better value with the argument
## `bins`.

variabel respon berdistribusi normal

Missing Values

Memeriksa apakah ada missing values pada data yang akan kita gunakan.

#Cek data hilang
anyNA(train.dataindex)
## [1] FALSE
sum(anyNA(train.dataindex))
## [1] 0

tidak ada data hilang

Generate Model

Pada tahap ini, kita akan membangun model dengan beberapa metode diantaranya best-subset, ridge, lasso, dan elastic-net.

Best-Subset Model

Pertama kita akan mencoba membangun model regresi dengan metode best-subset.

#Model regresi 
Mod_best<- lm(formula = Y~., data = train.dataindex)

#Summary model
summary(Mod_best)
## 
## Call:
## lm(formula = Y ~ ., data = train.dataindex)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -4.2256 -0.3381  0.0963  0.3282  4.2846 
## 
## Coefficients:
##               Estimate Std. Error  t value Pr(>|t|)    
## (Intercept)  2.542e+00  2.659e-01    9.558   <2e-16 ***
## V1           3.450e+00  3.354e-02  102.855   <2e-16 ***
## V2           3.496e+00  1.716e-02  203.755   <2e-16 ***
## V3           3.493e+00  3.947e-03  885.054   <2e-16 ***
## V4           3.494e+00  4.014e-03  870.545   <2e-16 ***
## V5           3.502e+00  3.928e-03  891.742   <2e-16 ***
## V6           3.500e+00  3.974e-03  880.779   <2e-16 ***
## V7           3.506e+00  3.960e-03  885.242   <2e-16 ***
## V8           3.498e+00  3.950e-03  885.575   <2e-16 ***
## V9           3.500e+00  3.942e-03  887.920   <2e-16 ***
## V10          3.496e+00  3.978e-03  878.734   <2e-16 ***
## V11          3.501e+00  4.039e-03  866.873   <2e-16 ***
## V12          3.509e+00  4.011e-03  874.663   <2e-16 ***
## V13          3.499e+00  3.943e-03  887.552   <2e-16 ***
## V14          3.501e+00  3.945e-03  887.411   <2e-16 ***
## V15          3.502e+00  3.942e-03  888.392   <2e-16 ***
## V16          3.501e+00  3.936e-03  889.564   <2e-16 ***
## V17          3.491e+00  4.048e-03  862.423   <2e-16 ***
## V18          3.505e+00  4.023e-03  871.229   <2e-16 ***
## V19          3.503e+00  3.975e-03  881.251   <2e-16 ***
## V20          3.495e+00  3.952e-03  884.398   <2e-16 ***
## V21         -2.670e-03  3.908e-03   -0.683   0.4945    
## V22         -2.924e-03  3.892e-03   -0.751   0.4525    
## V23         -1.509e-03  3.991e-03   -0.378   0.7054    
## V24         -5.948e-03  4.036e-03   -1.474   0.1405    
## V25         -1.902e-03  3.962e-03   -0.480   0.6312    
## V26         -2.184e-04  3.989e-03   -0.055   0.9563    
## V27         -9.050e-03  3.957e-03   -2.287   0.0222 *  
## V28          9.333e-04  3.968e-03    0.235   0.8141    
## V29          2.579e-03  3.954e-03    0.652   0.5143    
## V30         -1.937e-03  3.995e-03   -0.485   0.6277    
## V31         -9.729e-04  3.965e-03   -0.245   0.8062    
## V32          9.689e-05  3.959e-03    0.024   0.9805    
## V33          5.102e-03  3.982e-03    1.281   0.2002    
## V34          9.922e-04  3.981e-03    0.249   0.8032    
## V35         -2.666e-03  3.937e-03   -0.677   0.4983    
## V36          4.275e-03  3.946e-03    1.083   0.2787    
## V37         -9.511e-03  3.904e-03   -2.437   0.0148 *  
## V38          1.471e-03  3.978e-03    0.370   0.7116    
## V39          1.474e-03  4.002e-03    0.368   0.7127    
## V40          5.177e-04  4.011e-03    0.129   0.8973    
## V41          8.871e-04  3.919e-03    0.226   0.8209    
## V42         -5.734e-03  3.970e-03   -1.444   0.1487    
## V43         -2.044e-03  3.933e-03   -0.520   0.6032    
## V44         -3.273e-03  3.976e-03   -0.823   0.4105    
## V45         -2.258e-03  3.989e-03   -0.566   0.5714    
## V46          6.746e-04  4.000e-03    0.169   0.8661    
## V47          3.829e-03  3.926e-03    0.975   0.3295    
## V48         -1.578e-03  3.985e-03   -0.396   0.6921    
## V49          2.964e-03  4.001e-03    0.741   0.4589    
## V50          3.860e-03  3.929e-03    0.982   0.3260    
## V51         -4.488e+00  9.713e-03 -462.023   <2e-16 ***
## V52         -4.517e+00  1.189e-02 -379.898   <2e-16 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.9608 on 7949 degrees of freedom
## Multiple R-squared:  0.9996, Adjusted R-squared:  0.9996 
## F-statistic: 3.756e+05 on 52 and 7949 DF,  p-value: < 2.2e-16

Seleksi variabel dengan metode forward dan backward

#forward Selection
mod_forwd<-ols_step_forward_aic(Mod_best, details = T )
## Forward Selection Method 
## ------------------------
## 
## Candidate Terms: 
## 
## 1 . V1 
## 2 . V2 
## 3 . V3 
## 4 . V4 
## 5 . V5 
## 6 . V6 
## 7 . V7 
## 8 . V8 
## 9 . V9 
## 10 . V10 
## 11 . V11 
## 12 . V12 
## 13 . V13 
## 14 . V14 
## 15 . V15 
## 16 . V16 
## 17 . V17 
## 18 . V18 
## 19 . V19 
## 20 . V20 
## 21 . V21 
## 22 . V22 
## 23 . V23 
## 24 . V24 
## 25 . V25 
## 26 . V26 
## 27 . V27 
## 28 . V28 
## 29 . V29 
## 30 . V30 
## 31 . V31 
## 32 . V32 
## 33 . V33 
## 34 . V34 
## 35 . V35 
## 36 . V36 
## 37 . V37 
## 38 . V38 
## 39 . V39 
## 40 . V40 
## 41 . V41 
## 42 . V42 
## 43 . V43 
## 44 . V44 
## 45 . V45 
## 46 . V46 
## 47 . V47 
## 48 . V48 
## 49 . V49 
## 50 . V50 
## 51 . V51 
## 52 . V52 
## 
##  Step 0: AIC = 84491.59 
##  Y ~ 1 
## 
## ---------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq           RSS         R-Sq     Adj. R-Sq 
## ---------------------------------------------------------------------------------
## V51           1    82368.667    4206265.441    13829712.490    0.233        0.233 
## V1            1    82865.118    3321083.232    14714894.698    0.184        0.184 
## V2            1    83221.425    2651063.397    15384914.533    0.147        0.147 
## V15           1    84144.678     769530.179    17266447.752    0.043        0.043 
## V20           1    84153.770     749900.071    17286077.859    0.042        0.041 
## V6            1    84154.325     748700.329    17287277.602    0.042        0.041 
## V16           1    84159.500     737517.834    17298460.097    0.041        0.041 
## V7            1    84161.983     732148.507    17303829.424    0.041        0.040 
## V14           1    84163.207     729501.909    17306476.022    0.040        0.040 
## V18           1    84166.860     721598.640    17314379.291    0.040        0.040 
## V13           1    84167.183     720899.728    17315078.202    0.040        0.040 
## V17           1    84174.172     705771.314    17330206.616    0.039        0.039 
## V4            1    84187.707     676433.210    17359544.720    0.038        0.037 
## V10           1    84191.704     667759.306    17368218.625    0.037        0.037 
## V12           1    84191.901     667330.745    17368647.186    0.037        0.037 
## V3            1    84196.721     656867.497    17379110.434    0.036        0.036 
## V11           1    84198.112     653846.071    17382131.859    0.036        0.036 
## V19           1    84200.465     648733.850    17387244.080    0.036        0.036 
## V5            1    84211.017     625789.235    17410188.696    0.035        0.035 
## V9            1    84220.328     605520.927    17430457.003    0.034        0.033 
## V8            1    84233.859     576020.624    17459957.307    0.032        0.032 
## V30           1    84489.813       8515.745    18027462.185    0.000        0.000 
## V35           1    84490.528       6902.791    18029075.140    0.000        0.000 
## V21           1    84491.282       5203.917    18030774.014    0.000        0.000 
## V45           1    84491.322       5115.268    18030862.662    0.000        0.000 
## V28           1    84492.227       3074.682    18032903.249    0.000        0.000 
## V31           1    84492.244       3037.811    18032940.119    0.000        0.000 
## V34           1    84492.275       2968.010    18033009.921    0.000        0.000 
## V49           1    84492.289       2936.172    18033041.759    0.000        0.000 
## V40           1    84492.375       2742.962    18033234.969    0.000        0.000 
## V39           1    84492.648       2126.704    18033851.227    0.000        0.000 
## V25           1    84492.675       2065.292    18033912.639    0.000        0.000 
## V22           1    84492.723       1957.432    18034020.499    0.000        0.000 
## V33           1    84492.797       1791.240    18034186.691    0.000        0.000 
## V41           1    84492.965       1413.326    18034564.605    0.000        0.000 
## V23           1    84492.975       1388.988    18034588.943    0.000        0.000 
## V46           1    84493.010       1310.046    18034667.885    0.000        0.000 
## V50           1    84493.120       1062.993    18034914.937    0.000        0.000 
## V47           1    84493.173        943.103    18035034.827    0.000        0.000 
## V52           1    84493.221        834.715    18035143.216    0.000        0.000 
## V48           1    84493.313        627.880    18035350.050    0.000        0.000 
## V32           1    84493.326        598.339    18035379.592    0.000        0.000 
## V27           1    84493.416        394.817    18035583.114    0.000        0.000 
## V44           1    84493.423        379.845    18035598.085    0.000        0.000 
## V29           1    84493.482        247.283    18035730.648    0.000        0.000 
## V38           1    84493.521        159.066    18035818.865    0.000        0.000 
## V37           1    84493.556         79.197    18035898.734    0.000        0.000 
## V42           1    84493.570         49.048    18035928.883    0.000        0.000 
## V43           1    84493.576         36.236    18035941.694    0.000        0.000 
## V24           1    84493.584         17.499    18035960.431    0.000        0.000 
## V36           1    84493.588          6.981    18035970.950    0.000        0.000 
## V26           1    84493.590          4.167    18035973.763    0.000        0.000 
## ---------------------------------------------------------------------------------
## 
## 
## - V51 
## 
## 
##  Step 1 : AIC = 82368.67 
##  Y ~ V51 
## 
## ---------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq           RSS         R-Sq     Adj. R-Sq 
## ---------------------------------------------------------------------------------
## V52           1    81673.595    1153754.618    12675957.872    0.297        0.297 
## V1            1    81875.537     829788.284    12999924.206    0.279        0.279 
## V15           1    81894.799     798456.836    13031255.654    0.277        0.277 
## V18           1    81924.634     749780.456    13079932.034    0.275        0.275 
## V14           1    81933.469     735331.484    13094381.006    0.274        0.274 
## V20           1    81934.513     733622.523    13096089.967    0.274        0.274 
## V16           1    81936.837     729818.829    13099893.661    0.274        0.273 
## V7            1    81938.451     727175.634    13102536.855    0.274        0.273 
## V6            1    81943.901     718248.736    13111463.754    0.273        0.273 
## V12           1    81953.821     701984.248    13127728.242    0.272        0.272 
## V5            1    81965.718     682452.786    13147259.704    0.271        0.271 
## V4            1    81968.383     678072.378    13151640.112    0.271        0.271 
## V10           1    81970.795     674108.172    13155604.318    0.271        0.270 
## V17           1    81973.986     668861.760    13160850.730    0.270        0.270 
## V9            1    81977.683     662778.657    13166933.832    0.270        0.270 
## V19           1    81980.021     658932.418    13170780.072    0.270        0.270 
## V3            1    81983.114     653839.312    13175873.178    0.269        0.269 
## V13           1    81989.382     643514.476    13186198.014    0.269        0.269 
## V11           1    82003.489     620248.770    13209463.720    0.268        0.267 
## V8            1    82014.339     602324.952    13227387.538    0.267        0.266 
## V2            1    82052.910     538412.808    13291299.681    0.263        0.263 
## V35           1    82364.940       9893.964    13819818.525    0.234        0.234 
## V28           1    82368.545       3667.729    13826044.761    0.233        0.233 
## V30           1    82368.634       3513.216    13826199.273    0.233        0.233 
## V21           1    82368.829       3175.932    13826536.558    0.233        0.233 
## V47           1    82368.988       2901.108    13826811.382    0.233        0.233 
## V22           1    82369.066       2767.138    13826945.352    0.233        0.233 
## V34           1    82369.072       2755.785    13826956.704    0.233        0.233 
## V33           1    82369.450       2102.398    13827610.092    0.233        0.233 
## V50           1    82369.537       1952.226    13827760.263    0.233        0.233 
## V36           1    82369.579       1881.057    13827831.433    0.233        0.233 
## V41           1    82369.689       1690.950    13828021.540    0.233        0.233 
## V40           1    82369.732       1616.073    13828096.417    0.233        0.233 
## V45           1    82369.848       1415.579    13828296.911    0.233        0.233 
## V44           1    82369.860       1394.229    13828318.261    0.233        0.233 
## V39           1    82369.987       1175.861    13828536.629    0.233        0.233 
## V25           1    82370.115        953.868    13828758.622    0.233        0.233 
## V29           1    82370.227        760.911    13828951.579    0.233        0.233 
## V32           1    82370.260        702.795    13829009.695    0.233        0.233 
## V48           1    82370.320        599.168    13829113.321    0.233        0.233 
## V27           1    82370.437        397.388    13829315.102    0.233        0.233 
## V49           1    82370.440        393.134    13829319.356    0.233        0.233 
## V31           1    82370.509        273.961    13829438.528    0.233        0.233 
## V24           1    82370.513        266.095    13829446.394    0.233        0.233 
## V42           1    82370.537        224.385    13829488.105    0.233        0.233 
## V46           1    82370.591        131.520    13829580.970    0.233        0.233 
## V23           1    82370.615         90.570    13829621.919    0.233        0.233 
## V26           1    82370.617         85.986    13829626.504    0.233        0.233 
## V43           1    82370.623         75.503    13829636.987    0.233        0.233 
## V38           1    82370.659         13.329    13829699.161    0.233        0.233 
## V37           1    82370.664          4.647    13829707.842    0.233        0.233 
## ---------------------------------------------------------------------------------
## 
## - V52 
## 
## 
##  Step 2 : AIC = 81673.59 
##  Y ~ V51 + V52 
## 
## --------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq          RSS         R-Sq     Adj. R-Sq 
## --------------------------------------------------------------------------------
## V15           1    81164.271    784651.204    11891306.668    0.341        0.340 
## V20           1    81189.050    747770.984    11928186.887    0.339        0.338 
## V14           1    81190.307    745897.732    11930060.140    0.339        0.338 
## V16           1    81190.933    744963.751    11930994.121    0.338        0.338 
## V6            1    81195.608    737992.092    11937965.780    0.338        0.338 
## V18           1    81203.001    726956.774    11949001.098    0.337        0.337 
## V7            1    81212.339    713005.515    11962952.357    0.337        0.336 
## V10           1    81220.839    700290.732    11975667.140    0.336        0.336 
## V12           1    81232.237    683220.691    11992737.181    0.335        0.335 
## V5            1    81232.380    683006.962    11992950.910    0.335        0.335 
## V4            1    81235.431    678432.235    11997525.637    0.335        0.335 
## V17           1    81238.154    674349.741    12001608.131    0.335        0.334 
## V19           1    81258.781    643372.991    12032584.881    0.333        0.333 
## V3            1    81263.060    636936.388    12039021.484    0.332        0.332 
## V9            1    81264.394    634929.863    12041028.009    0.332        0.332 
## V13           1    81284.413    604768.405    12071189.467    0.331        0.330 
## V11           1    81285.240    603520.344    12072437.528    0.331        0.330 
## V8            1    81297.403    585156.708    12090801.164    0.330        0.329 
## V2            1    81666.825     13885.208    12662072.664    0.298        0.298 
## V35           1    81671.958      5760.033    12670197.839    0.298        0.297 
## V1            1    81672.133      5482.107    12670475.765    0.297        0.297 
## V28           1    81672.479      4934.912    12671022.960    0.297        0.297 
## V22           1    81673.750      2922.491    12673035.381    0.297        0.297 
## V21           1    81673.870      2732.697    12673225.175    0.297        0.297 
## V34           1    81673.917      2657.613    12673300.259    0.297        0.297 
## V30           1    81674.124      2329.999    12673627.873    0.297        0.297 
## V41           1    81674.306      2040.952    12673916.920    0.297        0.297 
## V45           1    81674.349      1973.149    12673984.723    0.297        0.297 
## V40           1    81674.420      1860.422    12674097.450    0.297        0.297 
## V47           1    81674.640      1512.176    12674445.696    0.297        0.297 
## V29           1    81674.787      1279.512    12674678.360    0.297        0.297 
## V32           1    81674.794      1269.230    12674688.642    0.297        0.297 
## V48           1    81674.843      1191.153    12674766.719    0.297        0.297 
## V25           1    81674.920      1069.325    12674888.547    0.297        0.297 
## V49           1    81674.937      1042.011    12674915.861    0.297        0.297 
## V36           1    81674.940      1038.018    12674919.854    0.297        0.297 
## V46           1    81674.997       947.280    12675010.592    0.297        0.297 
## V24           1    81675.004       935.889    12675021.983    0.297        0.297 
## V33           1    81675.045       870.813    12675087.059    0.297        0.297 
## V39           1    81675.051       861.193    12675096.679    0.297        0.297 
## V26           1    81675.068       834.607    12675123.265    0.297        0.297 
## V42           1    81675.151       703.640    12675254.232    0.297        0.297 
## V31           1    81675.245       554.785    12675403.087    0.297        0.297 
## V44           1    81675.286       489.924    12675467.947    0.297        0.297 
## V27           1    81675.498       153.680    12675804.192    0.297        0.297 
## V50           1    81675.513       129.658    12675828.214    0.297        0.297 
## V37           1    81675.557        59.877    12675897.995    0.297        0.297 
## V23           1    81675.587        12.939    12675944.933    0.297        0.297 
## V38           1    81675.587        12.540    12675945.332    0.297        0.297 
## V43           1    81675.594         0.705    12675957.167    0.297        0.297 
## --------------------------------------------------------------------------------
## 
## - V15 
## 
## 
##  Step 3 : AIC = 81164.27 
##  Y ~ V51 + V52 + V15 
## 
## --------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq          RSS         R-Sq     Adj. R-Sq 
## --------------------------------------------------------------------------------
## V20           1    80643.109    752571.190    11138735.478    0.382        0.382 
## V16           1    80652.902    738931.175    11152375.492    0.382        0.381 
## V14           1    80653.285    738397.346    11152909.321    0.382        0.381 
## V18           1    80662.614    725387.404    11165919.264    0.381        0.381 
## V7            1    80670.499    714379.966    11176926.702    0.380        0.380 
## V6            1    80673.942    709569.518    11181737.150    0.380        0.380 
## V10           1    80687.794    690195.769    11201110.899    0.379        0.379 
## V4            1    80697.005    677295.053    11214011.615    0.378        0.378 
## V5            1    80697.782    676206.043    11215100.625    0.378        0.378 
## V3            1    80699.136    674309.104    11216997.563    0.378        0.378 
## V12           1    80706.878    663451.352    11227855.316    0.377        0.377 
## V17           1    80713.221    654546.774    11236759.894    0.377        0.377 
## V19           1    80719.269    646051.086    11245255.581    0.377        0.376 
## V9            1    80729.713    631363.752    11259942.915    0.376        0.375 
## V11           1    80740.292    616468.338    11274838.330    0.375        0.375 
## V13           1    80740.937    615560.247    11275746.421    0.375        0.375 
## V8            1    80775.483    566775.477    11324531.190    0.372        0.372 
## V2            1    81156.765     14118.433    11877188.235    0.341        0.341 
## V1            1    81162.765      5209.525    11886097.143    0.341        0.341 
## V35           1    81163.025      4822.654    11886484.013    0.341        0.341 
## V34           1    81164.296      2934.251    11888372.417    0.341        0.341 
## V28           1    81164.310      2913.436    11888393.232    0.341        0.341 
## V41           1    81164.408      2768.849    11888537.819    0.341        0.341 
## V40           1    81164.525      2593.802    11888712.865    0.341        0.341 
## V30           1    81164.541      2571.066    11888735.602    0.341        0.341 
## V21           1    81164.804      2179.757    11889126.910    0.341        0.340 
## V47           1    81165.069      1786.025    11889520.642    0.341        0.340 
## V45           1    81165.138      1683.271    11889623.396    0.341        0.340 
## V22           1    81165.181      1619.752    11889686.916    0.341        0.340 
## V42           1    81165.349      1369.950    11889936.718    0.341        0.340 
## V49           1    81165.354      1361.949    11889944.719    0.341        0.340 
## V26           1    81165.382      1320.597    11889986.070    0.341        0.340 
## V32           1    81165.432      1246.338    11890060.330    0.341        0.340 
## V25           1    81165.537      1090.143    11890216.525    0.341        0.340 
## V24           1    81165.659       909.456    11890397.212    0.341        0.340 
## V44           1    81165.710       834.089    11890472.579    0.341        0.340 
## V29           1    81165.736       794.871    11890511.796    0.341        0.340 
## V31           1    81165.768       746.873    11890559.794    0.341        0.340 
## V48           1    81165.769       746.470    11890560.198    0.341        0.340 
## V36           1    81165.887       570.637    11890736.030    0.341        0.340 
## V33           1    81165.901       549.267    11890757.401    0.341        0.340 
## V39           1    81165.918       524.132    11890782.536    0.341        0.340 
## V46           1    81166.053       324.359    11890982.308    0.341        0.340 
## V43           1    81166.145       186.958    11891119.710    0.341        0.340 
## V50           1    81166.183       130.660    11891176.007    0.341        0.340 
## V38           1    81166.192       117.332    11891189.335    0.341        0.340 
## V37           1    81166.212        87.033    11891219.635    0.341        0.340 
## V27           1    81166.219        77.789    11891228.879    0.341        0.340 
## V23           1    81166.243        41.998    11891264.669    0.341        0.340 
## --------------------------------------------------------------------------------
## 
## - V20 
## 
## 
##  Step 4 : AIC = 80643.11 
##  Y ~ V51 + V52 + V15 + V20 
## 
## --------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq          RSS         R-Sq     Adj. R-Sq 
## --------------------------------------------------------------------------------
## V16           1    80091.127    745052.154    10393683.324    0.424        0.423 
## V14           1    80097.445    736842.434    10401893.044    0.423        0.423 
## V18           1    80113.318    716188.694    10422546.784    0.422        0.422 
## V6            1    80124.650    701417.870    10437317.608    0.421        0.421 
## V7            1    80129.728    694792.454    10443943.024    0.421        0.421 
## V4            1    80136.615    685799.656    10452935.822    0.420        0.420 
## V3            1    80145.004    674835.712    10463899.766    0.420        0.419 
## V17           1    80152.004    665678.731    10473056.747    0.419        0.419 
## V5            1    80152.376    665191.517    10473543.961    0.419        0.419 
## V10           1    80152.792    664647.430    10474088.048    0.419        0.419 
## V12           1    80156.629    659623.069    10479112.409    0.419        0.419 
## V19           1    80166.056    647270.895    10491464.582    0.418        0.418 
## V9            1    80167.322    645610.463    10493125.014    0.418        0.418 
## V11           1    80188.050    618395.067    10520340.411    0.417        0.416 
## V13           1    80192.690    612292.791    10526442.687    0.416        0.416 
## V8            1    80218.268    578591.241    10560144.236    0.414        0.414 
## V2            1    80632.629     17358.797    11121376.681    0.383        0.383 
## V41           1    80642.511      3615.994    11135119.483    0.383        0.382 
## V35           1    80642.629      3452.035    11135283.442    0.383        0.382 
## V28           1    80642.980      2962.695    11135772.783    0.383        0.382 
## V1            1    80643.172      2696.630    11136038.847    0.383        0.382 
## V21           1    80643.233      2611.144    11136124.334    0.383        0.382 
## V47           1    80643.255      2581.073    11136154.404    0.383        0.382 
## V40           1    80643.308      2507.408    11136228.069    0.383        0.382 
## V30           1    80643.376      2412.324    11136323.154    0.383        0.382 
## V26           1    80644.108      1393.902    11137341.575    0.382        0.382 
## V31           1    80644.152      1331.610    11137403.868    0.382        0.382 
## V44           1    80644.241      1208.133    11137527.344    0.382        0.382 
## V34           1    80644.252      1193.359    11137542.119    0.382        0.382 
## V42           1    80644.316      1103.567    11137631.911    0.382        0.382 
## V36           1    80644.456       909.177    11137826.301    0.382        0.382 
## V29           1    80644.530       806.689    11137928.789    0.382        0.382 
## V45           1    80644.582       733.968    11138001.509    0.382        0.382 
## V49           1    80644.609       695.580    11138039.897    0.382        0.382 
## V32           1    80644.697       573.949    11138161.528    0.382        0.382 
## V24           1    80644.705       561.949    11138173.529    0.382        0.382 
## V22           1    80644.732       524.894    11138210.583    0.382        0.382 
## V43           1    80644.809       417.798    11138317.680    0.382        0.382 
## V25           1    80644.838       377.212    11138358.266    0.382        0.382 
## V39           1    80644.891       303.320    11138432.157    0.382        0.382 
## V50           1    80644.917       267.094    11138468.384    0.382        0.382 
## V37           1    80644.920       263.941    11138471.537    0.382        0.382 
## V48           1    80644.954       216.011    11138519.467    0.382        0.382 
## V33           1    80645.018       127.046    11138608.432    0.382        0.382 
## V46           1    80645.067        59.123    11138676.354    0.382        0.382 
## V23           1    80645.088        29.575    11138705.903    0.382        0.382 
## V38           1    80645.096        18.971    11138716.506    0.382        0.382 
## V27           1    80645.109         0.271    11138735.207    0.382        0.382 
## --------------------------------------------------------------------------------
## 
## - V16 
## 
## 
##  Step 5 : AIC = 80091.13 
##  Y ~ V51 + V52 + V15 + V20 + V16 
## 
## --------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq          RSS         R-Sq     Adj. R-Sq 
## --------------------------------------------------------------------------------
## V14           1    79524.715    712689.802     9680993.521    0.463        0.463 
## V18           1    79525.395    711866.910     9681816.413    0.463        0.463 
## V6            1    79535.436    699711.387     9693971.937    0.463        0.462 
## V7            1    79539.536    694743.102     9698940.222    0.462        0.462 
## V5            1    79549.892    682182.413     9711500.911    0.462        0.461 
## V4            1    79552.326    679227.902     9714455.422    0.461        0.461 
## V10           1    79554.667    676385.961     9717297.363    0.461        0.461 
## V12           1    79560.467    669339.574     9724343.749    0.461        0.460 
## V3            1    79567.480    660813.324     9732869.999    0.460        0.460 
## V17           1    79571.694    655686.758     9737996.566    0.460        0.460 
## V19           1    79573.630    653330.768     9740352.556    0.460        0.460 
## V11           1    79590.788    632422.634     9761260.689    0.459        0.458 
## V9            1    79597.230    624560.868     9769122.456    0.458        0.458 
## V13           1    79608.368    610954.373     9782728.951    0.458        0.457 
## V8            1    79625.616    589845.114     9803838.210    0.456        0.456 
## V2            1    80078.715     18702.583    10374980.741    0.425        0.424 
## V41           1    80088.379      6165.531    10387517.793    0.424        0.424 
## V1            1    80091.207      2493.670    10391189.653    0.424        0.423 
## V35           1    80091.260      2424.678    10391258.646    0.424        0.423 
## V21           1    80091.533      2069.912    10391613.412    0.424        0.423 
## V47           1    80091.538      2063.291    10391620.032    0.424        0.423 
## V28           1    80091.609      1971.586    10391711.737    0.424        0.423 
## V40           1    80091.632      1941.392    10391741.932    0.424        0.423 
## V30           1    80091.666      1897.676    10391785.647    0.424        0.423 
## V29           1    80092.136      1286.511    10392396.813    0.424        0.423 
## V25           1    80092.270      1112.848    10392570.476    0.424        0.423 
## V44           1    80092.272      1110.262    10392573.062    0.424        0.423 
## V26           1    80092.351      1008.005    10392675.318    0.424        0.423 
## V42           1    80092.551       747.869    10392935.455    0.424        0.423 
## V36           1    80092.560       735.729    10392947.595    0.424        0.423 
## V45           1    80092.576       715.574    10392967.750    0.424        0.423 
## V22           1    80092.592       695.332    10392987.991    0.424        0.423 
## V48           1    80092.599       685.798    10392997.526    0.424        0.423 
## V31           1    80092.611       670.548    10393012.776    0.424        0.423 
## V46           1    80092.672       590.781    10393092.543    0.424        0.423 
## V50           1    80092.733       512.104    10393171.219    0.424        0.423 
## V34           1    80092.753       485.757    10393197.567    0.424        0.423 
## V24           1    80092.761       474.710    10393208.614    0.424        0.423 
## V32           1    80092.824       393.624    10393289.700    0.424        0.423 
## V27           1    80092.868       335.951    10393347.373    0.424        0.423 
## V39           1    80092.900       294.687    10393388.637    0.424        0.423 
## V49           1    80092.967       207.781    10393475.542    0.424        0.423 
## V43           1    80093.048       102.234    10393581.090    0.424        0.423 
## V23           1    80093.055        92.880    10393590.443    0.424        0.423 
## V33           1    80093.087        51.483    10393631.841    0.424        0.423 
## V38           1    80093.096        40.655    10393642.669    0.424        0.423 
## V37           1    80093.096        40.508    10393642.816    0.424        0.423 
## --------------------------------------------------------------------------------
## 
## - V14 
## 
## 
##  Step 6 : AIC = 79524.72 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 
## 
## -------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq          RSS        R-Sq     Adj. R-Sq 
## -------------------------------------------------------------------------------
## V7            1    78907.750    720608.166    8960385.356    0.503        0.503 
## V12           1    78928.079    697815.000    8983178.521    0.502        0.501 
## V3            1    78931.684    693767.898    8987225.623    0.502        0.501 
## V6            1    78933.817    691372.079    8989621.443    0.502        0.501 
## V5            1    78938.506    686102.225    8994891.297    0.501        0.501 
## V18           1    78949.893    673293.733    9007699.788    0.501        0.500 
## V10           1    78951.907    671025.581    9009967.940    0.500        0.500 
## V19           1    78957.432    664802.926    9016190.595    0.500        0.500 
## V4            1    78964.197    657177.137    9023816.385    0.500        0.499 
## V17           1    78972.383    647941.455    9033052.067    0.499        0.499 
## V9            1    78984.311    634465.896    9046527.626    0.498        0.498 
## V11           1    78997.550    619487.030    9061506.491    0.498        0.497 
## V8            1    79006.792    609015.512    9071978.009    0.497        0.497 
## V13           1    79018.271    595991.896    9085001.626    0.496        0.496 
## V2            1    79514.228     15095.800    9665897.722    0.464        0.464 
## V41           1    79522.444      5166.044    9675827.477    0.464        0.463 
## V1            1    79523.565      3810.609    9677182.912    0.463        0.463 
## V40           1    79524.658      2488.049    9678505.472    0.463        0.463 
## V35           1    79524.742      2386.455    9678607.067    0.463        0.463 
## V47           1    79524.810      2305.203    9678688.319    0.463        0.463 
## V21           1    79525.231      1794.839    9679198.682    0.463        0.463 
## V26           1    79525.370      1626.722    9679366.800    0.463        0.463 
## V30           1    79525.471      1504.973    9679488.549    0.463        0.463 
## V25           1    79525.591      1360.446    9679633.075    0.463        0.463 
## V48           1    79525.597      1352.751    9679640.770    0.463        0.463 
## V42           1    79525.609      1337.951    9679655.570    0.463        0.463 
## V44           1    79525.685      1245.735    9679747.787    0.463        0.463 
## V24           1    79525.954       921.070    9680072.451    0.463        0.463 
## V28           1    79525.969       902.360    9680091.162    0.463        0.463 
## V50           1    79525.995       871.676    9680121.846    0.463        0.463 
## V45           1    79526.016       845.732    9680147.790    0.463        0.463 
## V46           1    79526.131       706.998    9680286.523    0.463        0.463 
## V27           1    79526.182       644.524    9680348.997    0.463        0.463 
## V29           1    79526.208       613.970    9680379.551    0.463        0.463 
## V31           1    79526.241       573.393    9680420.128    0.463        0.463 
## V36           1    79526.246       567.201    9680426.321    0.463        0.463 
## V34           1    79526.358       431.822    9680561.700    0.463        0.463 
## V38           1    79526.402       378.369    9680615.153    0.463        0.463 
## V22           1    79526.444       327.485    9680666.036    0.463        0.463 
## V37           1    79526.528       226.820    9680766.702    0.463        0.463 
## V43           1    79526.545       205.973    9680787.548    0.463        0.463 
## V32           1    79526.571       174.922    9680818.599    0.463        0.463 
## V39           1    79526.637        94.370    9680899.151    0.463        0.463 
## V49           1    79526.694        25.563    9680967.958    0.463        0.463 
## V23           1    79526.700        18.013    9680975.508    0.463        0.463 
## V33           1    79526.713         3.165    9680990.357    0.463        0.463 
## -------------------------------------------------------------------------------
## 
## - V7 
## 
## 
##  Step 7 : AIC = 78907.75 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 
## 
## -------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq          RSS        R-Sq     Adj. R-Sq 
## -------------------------------------------------------------------------------
## V6            1    78258.066    700811.169    8259574.187    0.542        0.542 
## V5            1    78269.684    688809.603    8271575.752    0.541        0.541 
## V10           1    78273.558    684804.372    8275580.984    0.541        0.541 
## V19           1    78275.617    682675.068    8277710.288    0.541        0.541 
## V12           1    78276.716    681538.319    8278847.037    0.541        0.541 
## V3            1    78281.913    676159.041    8284226.314    0.541        0.540 
## V18           1    78285.854    672078.322    8288307.033    0.540        0.540 
## V17           1    78293.037    664635.273    8295750.083    0.540        0.540 
## V9            1    78309.702    647340.229    8313045.126    0.539        0.539 
## V4            1    78312.759    644163.536    8316221.820    0.539        0.538 
## V13           1    78344.831    610765.853    8349619.503    0.537        0.537 
## V11           1    78352.650    602602.750    8357782.606    0.537        0.536 
## V8            1    78360.477    594424.084    8365961.272    0.536        0.536 
## V2            1    78895.498     15945.304    8944440.052    0.504        0.504 
## V47           1    78906.640      3482.297    8956903.058    0.503        0.503 
## V41           1    78906.849      3248.053    8957137.302    0.503        0.503 
## V35           1    78907.239      2811.860    8957573.496    0.503        0.503 
## V26           1    78907.281      2764.020    8957621.335    0.503        0.503 
## V1            1    78907.369      2666.018    8957719.337    0.503        0.503 
## V25           1    78907.684      2313.120    8958072.235    0.503        0.503 
## V48           1    78907.948      2017.384    8958367.971    0.503        0.503 
## V40           1    78907.981      1980.716    8958404.640    0.503        0.503 
## V44           1    78908.423      1485.654    8958899.701    0.503        0.503 
## V30           1    78908.647      1234.580    8959150.776    0.503        0.503 
## V45           1    78908.712      1162.632    8959222.724    0.503        0.503 
## V21           1    78908.954       891.589    8959493.767    0.503        0.503 
## V50           1    78909.019       818.560    8959566.796    0.503        0.503 
## V28           1    78909.082       747.937    8959637.419    0.503        0.503 
## V49           1    78909.117       708.651    8959676.705    0.503        0.503 
## V24           1    78909.128       697.042    8959688.314    0.503        0.503 
## V31           1    78909.165       654.826    8959730.530    0.503        0.503 
## V22           1    78909.303       500.484    8959884.872    0.503        0.503 
## V36           1    78909.348       450.377    8959934.979    0.503        0.503 
## V34           1    78909.356       441.091    8959944.265    0.503        0.503 
## V32           1    78909.398       394.122    8959991.234    0.503        0.503 
## V27           1    78909.468       315.980    8960069.376    0.503        0.503 
## V43           1    78909.486       296.040    8960089.315    0.503        0.503 
## V46           1    78909.577       193.870    8960191.485    0.503        0.503 
## V39           1    78909.615       151.310    8960234.046    0.503        0.503 
## V42           1    78909.621       144.513    8960240.843    0.503        0.503 
## V38           1    78909.625       140.365    8960244.991    0.503        0.503 
## V29           1    78909.686        71.206    8960314.150    0.503        0.503 
## V23           1    78909.705        50.929    8960334.426    0.503        0.503 
## V37           1    78909.744         6.239    8960379.116    0.503        0.503 
## V33           1    78909.749         1.496    8960383.859    0.503        0.503 
## -------------------------------------------------------------------------------
## 
## - V6 
## 
## 
##  Step 8 : AIC = 78258.07 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 
## 
## -------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq          RSS        R-Sq     Adj. R-Sq 
## -------------------------------------------------------------------------------
## V5            1    77566.468    685774.022    7573800.165    0.580        0.580 
## V10           1    77569.411    682987.404    7576586.783    0.580        0.579 
## V19           1    77576.798    675990.207    7583583.980    0.580        0.579 
## V12           1    77578.043    674810.171    7584764.016    0.579        0.579 
## V3            1    77578.455    674419.477    7585154.710    0.579        0.579 
## V9            1    77588.600    664796.819    7594777.368    0.579        0.578 
## V4            1    77598.912    655003.305    7604570.882    0.578        0.578 
## V17           1    77601.520    652524.336    7607049.851    0.578        0.578 
## V18           1    77608.923    645483.533    7614090.654    0.578        0.577 
## V13           1    77635.870    619799.848    7639774.339    0.576        0.576 
## V11           1    77639.743    616100.820    7643473.367    0.576        0.576 
## V8            1    77642.948    613039.155    7646535.032    0.576        0.576 
## V2            1    78237.947     22798.924    8236775.263    0.543        0.543 
## V35           1    78256.107      4084.521    8255489.666    0.542        0.542 
## V41           1    78256.864      3304.208    8256269.979    0.542        0.542 
## V26           1    78257.571      2574.407    8256999.780    0.542        0.542 
## V47           1    78257.652      2490.704    8257083.483    0.542        0.542 
## V48           1    78258.656      1454.589    8258119.598    0.542        0.542 
## V25           1    78258.712      1397.390    8258176.797    0.542        0.542 
## V30           1    78258.730      1378.418    8258195.769    0.542        0.542 
## V50           1    78258.805      1300.927    8258273.260    0.542        0.542 
## V44           1    78258.896      1207.620    8258366.567    0.542        0.542 
## V1            1    78258.987      1113.190    8258460.996    0.542        0.542 
## V36           1    78259.313       776.390    8258797.797    0.542        0.542 
## V21           1    78259.326       762.866    8258811.321    0.542        0.542 
## V32           1    78259.340       748.795    8258825.392    0.542        0.542 
## V40           1    78259.461       623.631    8258950.556    0.542        0.542 
## V28           1    78259.550       532.635    8259041.552    0.542        0.542 
## V24           1    78259.674       404.209    8259169.978    0.542        0.542 
## V22           1    78259.682       395.703    8259178.484    0.542        0.542 
## V42           1    78259.820       253.005    8259321.182    0.542        0.542 
## V38           1    78259.842       231.261    8259342.926    0.542        0.542 
## V45           1    78259.885       186.784    8259387.403    0.542        0.542 
## V49           1    78259.892       179.151    8259395.036    0.542        0.542 
## V46           1    78259.906       164.269    8259409.918    0.542        0.542 
## V23           1    78259.911       159.529    8259414.658    0.542        0.542 
## V34           1    78259.924       146.483    8259427.704    0.542        0.542 
## V39           1    78259.935       135.229    8259438.958    0.542        0.542 
## V31           1    78259.980        88.671    8259485.516    0.542        0.542 
## V43           1    78259.987        81.540    8259492.647    0.542        0.542 
## V27           1    78259.994        74.342    8259499.845    0.542        0.542 
## V29           1    78260.040        26.186    8259548.001    0.542        0.542 
## V33           1    78260.062         3.192    8259570.995    0.542        0.542 
## V37           1    78260.065         0.967    8259573.220    0.542        0.542 
## -------------------------------------------------------------------------------
## 
## - V5 
## 
## 
##  Step 9 : AIC = 77566.47 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 
## 
## -------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq          RSS        R-Sq     Adj. R-Sq 
## -------------------------------------------------------------------------------
## V12           1    76819.889    676389.679    6897410.486    0.618        0.617 
## V19           1    76820.964    675463.240    6898336.925    0.618        0.617 
## V3            1    76821.214    675247.850    6898552.315    0.618        0.617 
## V10           1    76823.981    672861.621    6900938.544    0.617        0.617 
## V9            1    76834.870    663464.636    6910335.528    0.617        0.616 
## V18           1    76838.245    660549.477    6913250.688    0.617        0.616 
## V17           1    76842.972    656464.214    6917335.951    0.616        0.616 
## V4            1    76849.470    650845.220    6922954.945    0.616        0.616 
## V8            1    76864.411    637906.878    6935893.287    0.615        0.615 
## V13           1    76875.366    628404.484    6945395.681    0.615        0.614 
## V11           1    76880.374    624056.236    6949743.929    0.615        0.614 
## V2            1    77543.403     23686.537    7550113.628    0.581        0.581 
## V41           1    77565.289      3007.825    7570792.340    0.580        0.580 
## V35           1    77565.309      2988.782    7570811.383    0.580        0.580 
## V48           1    77565.767      2555.706    7571244.459    0.580        0.580 
## V32           1    77566.030      2306.766    7571493.399    0.580        0.580 
## V21           1    77566.429      1929.224    7571870.940    0.580        0.580 
## V25           1    77566.464      1895.753    7571904.412    0.580        0.580 
## V30           1    77566.637      1732.180    7572067.985    0.580        0.580 
## V1            1    77567.213      1186.856    7572613.309    0.580        0.580 
## V26           1    77567.384      1025.630    7572774.534    0.580        0.580 
## V47           1    77567.456       956.873    7572843.292    0.580        0.580 
## V24           1    77567.505       910.538    7572889.627    0.580        0.580 
## V36           1    77567.517       899.577    7572900.588    0.580        0.580 
## V40           1    77567.586       834.089    7572966.076    0.580        0.580 
## V50           1    77567.677       747.939    7573052.225    0.580        0.580 
## V43           1    77567.758       671.267    7573128.898    0.580        0.580 
## V31           1    77567.779       651.740    7573148.425    0.580        0.580 
## V44           1    77567.926       512.593    7573287.572    0.580        0.580 
## V28           1    77567.944       495.386    7573304.779    0.580        0.580 
## V49           1    77568.081       365.426    7573434.739    0.580        0.580 
## V34           1    77568.097       351.095    7573449.070    0.580        0.580 
## V27           1    77568.248       208.098    7573592.067    0.580        0.580 
## V22           1    77568.321       138.237    7573661.928    0.580        0.580 
## V45           1    77568.351       110.168    7573689.997    0.580        0.580 
## V38           1    77568.358       103.703    7573696.462    0.580        0.580 
## V46           1    77568.373        89.140    7573711.025    0.580        0.580 
## V23           1    77568.389        74.639    7573725.526    0.580        0.580 
## V29           1    77568.399        64.840    7573735.325    0.580        0.580 
## V39           1    77568.415        50.031    7573750.134    0.580        0.580 
## V42           1    77568.434        31.652    7573768.513    0.580        0.580 
## V33           1    77568.439        26.717    7573773.448    0.580        0.580 
## V37           1    77568.467         0.124    7573800.040    0.580        0.580 
## -------------------------------------------------------------------------------
## 
## - V12 
## 
## 
##  Step 10 : AIC = 76819.89 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 + V12 
## 
## -------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq          RSS        R-Sq     Adj. R-Sq 
## -------------------------------------------------------------------------------
## V19           1    75959.278    704862.597    6192547.889    0.657        0.656 
## V10           1    75992.842    678833.555    6218576.931    0.655        0.655 
## V3            1    75995.749    676574.240    6220836.246    0.655        0.655 
## V18           1    76001.665    671973.673    6225436.813    0.655        0.654 
## V4            1    76016.967    660057.346    6237353.140    0.654        0.654 
## V13           1    76027.468    651866.787    6245543.699    0.654        0.653 
## V9            1    76037.520    644016.504    6253393.982    0.653        0.653 
## V17           1    76042.349    640241.455    6257169.031    0.653        0.653 
## V8            1    76050.149    634139.350    6263271.136    0.653        0.652 
## V11           1    76075.185    614512.812    6282897.674    0.652        0.651 
## V2            1    76790.502     27001.405    6870409.081    0.619        0.619 
## V41           1    76817.957      3388.636    6894021.850    0.618        0.617 
## V48           1    76818.645      2796.260    6894614.225    0.618        0.617 
## V35           1    76819.271      2256.570    6895153.916    0.618        0.617 
## V32           1    76819.384      2158.760    6895251.726    0.618        0.617 
## V30           1    76819.669      1913.879    6895496.607    0.618        0.617 
## V28           1    76820.292      1376.484    6896034.002    0.618        0.617 
## V25           1    76820.663      1057.291    6896353.195    0.618        0.617 
## V40           1    76820.668      1052.862    6896357.624    0.618        0.617 
## V21           1    76820.671      1050.183    6896360.303    0.618        0.617 
## V26           1    76820.785       951.586    6896458.900    0.618        0.617 
## V24           1    76820.799       939.913    6896470.573    0.618        0.617 
## V43           1    76820.984       780.623    6896629.863    0.618        0.617 
## V31           1    76821.115       667.651    6896742.835    0.618        0.617 
## V47           1    76821.121       662.341    6896748.145    0.618        0.617 
## V36           1    76821.214       581.712    6896828.774    0.618        0.617 
## V1            1    76821.311       498.408    6896912.077    0.618        0.617 
## V27           1    76821.461       369.517    6897040.969    0.618        0.617 
## V44           1    76821.463       367.632    6897042.853    0.618        0.617 
## V34           1    76821.521       317.473    6897093.013    0.618        0.617 
## V22           1    76821.582       265.126    6897145.360    0.618        0.617 
## V39           1    76821.602       247.958    6897162.528    0.618        0.617 
## V49           1    76821.608       242.335    6897168.151    0.618        0.617 
## V29           1    76821.714       151.131    6897259.355    0.618        0.617 
## V42           1    76821.737       131.431    6897279.055    0.618        0.617 
## V46           1    76821.746       123.178    6897287.308    0.618        0.617 
## V45           1    76821.812        66.999    6897343.486    0.618        0.617 
## V38           1    76821.820        59.724    6897350.762    0.618        0.617 
## V50           1    76821.831        50.033    6897360.453    0.618        0.617 
## V33           1    76821.874        13.498    6897396.987    0.618        0.617 
## V23           1    76821.875        12.163    6897398.323    0.618        0.617 
## V37           1    76821.889         0.427    6897410.059    0.618        0.617 
## -------------------------------------------------------------------------------
## 
## - V19 
## 
## 
##  Step 11 : AIC = 75959.28 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 + V12 + V19 
## 
## -------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq          RSS        R-Sq     Adj. R-Sq 
## -------------------------------------------------------------------------------
## V10           1    75009.700    694302.121    5498245.768    0.695        0.695 
## V3            1    75020.152    687115.682    5505432.207    0.695        0.694 
## V18           1    75037.388    675244.848    5517303.041    0.694        0.694 
## V4            1    75052.746    664645.522    5527902.367    0.694        0.693 
## V13           1    75065.610    655751.774    5536796.115    0.693        0.693 
## V17           1    75071.940    651369.856    5541178.032    0.693        0.692 
## V9            1    75102.044    630484.484    5562063.405    0.692        0.691 
## V8            1    75114.037    622141.879    5570406.010    0.691        0.691 
## V11           1    75135.921    606886.855    5585661.034    0.690        0.690 
## V2            1    75923.842     28903.590    6163644.299    0.658        0.658 
## V30           1    75957.592      2852.061    6189695.828    0.657        0.656 
## V41           1    75958.177      2399.737    6190148.152    0.657        0.656 
## V21           1    75959.089      1693.562    6190854.326    0.657        0.656 
## V48           1    75959.218      1593.852    6190954.037    0.657        0.656 
## V32           1    75959.438      1424.214    6191123.675    0.657        0.656 
## V25           1    75959.601      1297.748    6191250.141    0.657        0.656 
## V35           1    75959.993       994.143    6191553.746    0.657        0.656 
## V40           1    75960.084       923.761    6191624.128    0.657        0.656 
## V26           1    75960.325       737.614    6191810.275    0.657        0.656 
## V28           1    75960.394       684.165    6191863.724    0.657        0.656 
## V44           1    75960.411       670.871    6191877.018    0.657        0.656 
## V36           1    75960.516       589.656    6191958.233    0.657        0.656 
## V24           1    75960.518       588.399    6191959.489    0.657        0.656 
## V34           1    75960.575       543.856    6192004.032    0.657        0.656 
## V49           1    75960.701       446.877    6192101.012    0.657        0.656 
## V45           1    75960.727       426.442    6192121.447    0.657        0.656 
## V43           1    75960.757       402.937    6192144.952    0.657        0.656 
## V38           1    75960.779       386.517    6192161.372    0.657        0.656 
## V37           1    75960.842       337.693    6192210.196    0.657        0.656 
## V31           1    75960.886       303.456    6192244.432    0.657        0.656 
## V27           1    75960.986       226.080    6192321.809    0.657        0.656 
## V39           1    75961.057       170.956    6192376.933    0.657        0.656 
## V1            1    75961.062       167.573    6192380.316    0.657        0.656 
## V29           1    75961.068       162.817    6192385.072    0.657        0.656 
## V50           1    75961.081       152.278    6192395.611    0.657        0.656 
## V23           1    75961.117       124.792    6192423.097    0.657        0.656 
## V42           1    75961.124       119.642    6192428.247    0.657        0.656 
## V47           1    75961.154        95.963    6192451.926    0.657        0.656 
## V22           1    75961.213        50.165    6192497.723    0.657        0.656 
## V46           1    75961.251        21.036    6192526.853    0.657        0.656 
## V33           1    75961.256        17.477    6192530.412    0.657        0.656 
## -------------------------------------------------------------------------------
## 
## - V10 
## 
## 
##  Step 12 : AIC = 75009.7 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 + V12 + V19 + V10 
## 
## -------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq          RSS        R-Sq     Adj. R-Sq 
## -------------------------------------------------------------------------------
## V3            1    73942.448    687721.767    4810524.001    0.733        0.733 
## V4            1    73955.988    679575.487    4818670.281    0.733        0.732 
## V13           1    73969.143    671647.184    4826598.584    0.732        0.732 
## V18           1    73997.403    654571.383    4843674.385    0.731        0.731 
## V17           1    74001.450    652120.970    4846124.798    0.731        0.731 
## V9            1    74016.068    643259.784    4854985.984    0.731        0.730 
## V8            1    74019.928    640917.552    4857328.216    0.731        0.730 
## V11           1    74104.523    589294.725    4908951.043    0.728        0.727 
## V2            1    74975.006     25155.419    5473090.349    0.697        0.696 
## V41           1    75009.160      1744.948    5496500.820    0.695        0.695 
## V30           1    75009.337      1623.647    5496622.121    0.695        0.695 
## V48           1    75009.565      1466.681    5496779.087    0.695        0.695 
## V21           1    75009.902      1235.060    5497010.708    0.695        0.695 
## V44           1    75010.347       929.536    5497316.232    0.695        0.695 
## V36           1    75010.392       899.028    5497346.739    0.695        0.695 
## V32           1    75010.447       860.938    5497384.829    0.695        0.695 
## V35           1    75010.531       803.152    5497442.615    0.695        0.695 
## V28           1    75010.610       749.129    5497496.639    0.695        0.695 
## V42           1    75010.732       665.282    5497580.486    0.695        0.695 
## V49           1    75010.824       601.858    5497643.910    0.695        0.695 
## V40           1    75010.919       536.967    5497708.801    0.695        0.695 
## V29           1    75010.928       530.510    5497715.258    0.695        0.695 
## V45           1    75011.033       458.429    5497787.339    0.695        0.695 
## V27           1    75011.098       413.602    5497832.166    0.695        0.695 
## V31           1    75011.152       376.733    5497869.035    0.695        0.695 
## V37           1    75011.201       343.190    5497902.578    0.695        0.695 
## V26           1    75011.226       325.451    5497920.317    0.695        0.695 
## V38           1    75011.275       292.314    5497953.454    0.695        0.695 
## V34           1    75011.357       235.562    5498010.206    0.695        0.695 
## V39           1    75011.430       185.829    5498059.938    0.695        0.695 
## V1            1    75011.433       183.608    5498062.160    0.695        0.695 
## V24           1    75011.444       176.068    5498069.700    0.695        0.695 
## V25           1    75011.514       127.787    5498117.981    0.695        0.695 
## V22           1    75011.673        18.934    5498226.834    0.695        0.695 
## V50           1    75011.683        11.901    5498233.866    0.695        0.695 
## V43           1    75011.696         2.978    5498242.789    0.695        0.695 
## V47           1    75011.696         2.859    5498242.909    0.695        0.695 
## V33           1    75011.697         2.171    5498243.596    0.695        0.695 
## V46           1    75011.698         1.809    5498243.959    0.695        0.695 
## V23           1    75011.700         0.301    5498245.466    0.695        0.695 
## -------------------------------------------------------------------------------
## 
## - V3 
## 
## 
##  Step 13 : AIC = 73942.45 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 + V12 + V19 + V10 + V3 
## 
## -------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq          RSS        R-Sq     Adj. R-Sq 
## -------------------------------------------------------------------------------
## V13           1    72717.194    683991.100    4126532.901    0.771        0.771 
## V4            1    72725.311    679802.895    4130721.105    0.771        0.771 
## V8            1    72751.526    666248.269    4144275.731    0.770        0.770 
## V18           1    72757.896    662948.094    4147575.907    0.770        0.770 
## V17           1    72790.475    646027.425    4164496.576    0.769        0.769 
## V9            1    72798.935    641621.968    4168902.033    0.769        0.768 
## V11           1    72913.693    581404.293    4229119.707    0.766        0.765 
## V2            1    73897.555     28108.473    4782415.528    0.735        0.734 
## V30           1    73940.448      2404.116    4808119.884    0.733        0.733 
## V48           1    73941.307      1888.304    4808635.697    0.733        0.733 
## V42           1    73942.051      1441.072    4809082.929    0.733        0.733 
## V21           1    73942.057      1437.459    4809086.542    0.733        0.733 
## V28           1    73942.553      1138.973    4809385.027    0.733        0.733 
## V40           1    73942.976       885.101    4809638.900    0.733        0.733 
## V1            1    73943.007       866.143    4809657.858    0.733        0.733 
## V27           1    73943.072       827.167    4809696.834    0.733        0.733 
## V49           1    73943.279       703.031    4809820.970    0.733        0.733 
## V38           1    73943.312       682.942    4809841.059    0.733        0.733 
## V26           1    73943.424       615.813    4809908.187    0.733        0.733 
## V41           1    73943.590       515.752    4810008.248    0.733        0.733 
## V29           1    73943.672       466.531    4810057.469    0.733        0.733 
## V44           1    73943.676       464.287    4810059.713    0.733        0.733 
## V45           1    73943.756       416.228    4810107.772    0.733        0.733 
## V35           1    73943.871       346.908    4810177.092    0.733        0.733 
## V36           1    73943.904       327.395    4810196.605    0.733        0.733 
## V24           1    73944.083       219.595    4810304.405    0.733        0.733 
## V33           1    73944.148       180.377    4810343.623    0.733        0.733 
## V34           1    73944.173       165.558    4810358.443    0.733        0.733 
## V32           1    73944.179       161.799    4810362.201    0.733        0.733 
## V37           1    73944.187       157.111    4810366.890    0.733        0.733 
## V31           1    73944.269       107.977    4810416.024    0.733        0.733 
## V46           1    73944.320        77.140    4810446.860    0.733        0.733 
## V23           1    73944.343        63.555    4810460.446    0.733        0.733 
## V22           1    73944.403        27.388    4810496.612    0.733        0.733 
## V39           1    73944.414        20.794    4810503.206    0.733        0.733 
## V50           1    73944.435         8.038    4810515.962    0.733        0.733 
## V47           1    73944.436         7.307    4810516.694    0.733        0.733 
## V43           1    73944.439         5.467    4810518.533    0.733        0.733 
## V25           1    73944.448         0.218    4810523.783    0.733        0.733 
## -------------------------------------------------------------------------------
## 
## - V13 
## 
## 
##  Step 14 : AIC = 72717.19 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 + V12 + V19 + V10 + V3 + V13 
## 
## -------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq          RSS        R-Sq     Adj. R-Sq 
## -------------------------------------------------------------------------------
## V8            1    71273.942    681869.204    3444663.697    0.809        0.809 
## V4            1    71279.303    679560.704    3446972.197    0.809        0.809 
## V18           1    71299.960    670651.133    3455881.767    0.808        0.808 
## V17           1    71359.552    644818.500    3481714.401    0.807        0.807 
## V9            1    71370.342    640120.433    3486412.468    0.807        0.806 
## V11           1    71456.971    602171.937    3524360.964    0.805        0.804 
## V2            1    72664.969     27868.600    4098664.301    0.773        0.772 
## V42           1    72713.970      2692.993    4123839.908    0.771        0.771 
## V48           1    72715.246      2035.212    4124497.688    0.771        0.771 
## V1            1    72715.429      1941.138    4124591.762    0.771        0.771 
## V30           1    72716.545      1365.885    4125167.015    0.771        0.771 
## V27           1    72716.654      1309.703    4125223.197    0.771        0.771 
## V28           1    72717.573       835.780    4125697.120    0.771        0.771 
## V45           1    72717.587       828.586    4125704.314    0.771        0.771 
## V35           1    72718.313       454.284    4126078.616    0.771        0.771 
## V40           1    72718.428       395.113    4126137.788    0.771        0.771 
## V26           1    72718.445       386.078    4126146.823    0.771        0.771 
## V44           1    72718.446       385.774    4126147.127    0.771        0.771 
## V46           1    72718.486       364.924    4126167.977    0.771        0.771 
## V31           1    72718.496       360.133    4126172.767    0.771        0.771 
## V49           1    72718.564       325.072    4126207.829    0.771        0.771 
## V37           1    72718.829       188.146    4126344.755    0.771        0.771 
## V32           1    72718.912       145.525    4126387.375    0.771        0.771 
## V29           1    72718.928       136.995    4126395.906    0.771        0.771 
## V41           1    72718.978       111.504    4126421.397    0.771        0.771 
## V21           1    72718.987       106.488    4126426.413    0.771        0.771 
## V43           1    72719.025        87.290    4126445.611    0.771        0.771 
## V23           1    72719.043        77.955    4126454.946    0.771        0.771 
## V38           1    72719.055        71.402    4126461.499    0.771        0.771 
## V36           1    72719.127        34.607    4126498.294    0.771        0.771 
## V39           1    72719.136        29.653    4126503.248    0.771        0.771 
## V22           1    72719.138        28.734    4126504.167    0.771        0.771 
## V25           1    72719.142        26.882    4126506.019    0.771        0.771 
## V33           1    72719.155        20.012    4126512.889    0.771        0.771 
## V24           1    72719.164        15.362    4126517.539    0.771        0.771 
## V47           1    72719.182         6.036    4126526.865    0.771        0.771 
## V50           1    72719.185         4.680    4126528.220    0.771        0.771 
## V34           1    72719.188         2.942    4126529.959    0.771        0.771 
## -------------------------------------------------------------------------------
## 
## - V8 
## 
## 
##  Step 15 : AIC = 71273.94 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 + V12 + V19 + V10 + V3 + V13 + V8 
## 
## -------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq          RSS        R-Sq     Adj. R-Sq 
## -------------------------------------------------------------------------------
## V4            1    69508.379    682715.971    2761947.726    0.847        0.847 
## V18           1    69537.613    672607.429    2772056.268    0.846        0.846 
## V9            1    69554.485    666756.354    2777907.343    0.846        0.846 
## V17           1    69612.039    646704.398    2797959.299    0.845        0.845 
## V11           1    69717.379    609628.000    2835035.697    0.843        0.842 
## V2            1    71209.342     28550.796    3416112.901    0.811        0.810 
## V42           1    71270.831      2199.624    3442464.073    0.809        0.809 
## V1            1    71270.889      2174.669    3442489.028    0.809        0.809 
## V48           1    71272.760      1369.791    3443293.906    0.809        0.809 
## V40           1    71272.971      1279.014    3443384.683    0.809        0.809 
## V28           1    71274.210       745.695    3443918.002    0.809        0.809 
## V49           1    71274.292       710.464    3443953.233    0.809        0.809 
## V32           1    71274.378       673.455    3443990.242    0.809        0.809 
## V45           1    71274.545       601.672    3444062.025    0.809        0.809 
## V44           1    71274.618       570.276    3444093.421    0.809        0.809 
## V27           1    71274.654       554.435    3444109.262    0.809        0.809 
## V24           1    71274.698       535.782    3444127.915    0.809        0.809 
## V26           1    71274.915       442.364    3444221.333    0.809        0.809 
## V41           1    71275.195       321.866    3444341.831    0.809        0.809 
## V46           1    71275.198       320.525    3444343.172    0.809        0.809 
## V35           1    71275.314       270.652    3444393.045    0.809        0.809 
## V30           1    71275.326       265.551    3444398.146    0.809        0.809 
## V29           1    71275.465       205.341    3444458.356    0.809        0.809 
## V23           1    71275.499       191.081    3444472.616    0.809        0.809 
## V36           1    71275.518       182.761    3444480.936    0.809        0.809 
## V37           1    71275.555       166.958    3444496.739    0.809        0.809 
## V38           1    71275.597       148.871    3444514.826    0.809        0.809 
## V39           1    71275.761        77.991    3444585.706    0.809        0.809 
## V47           1    71275.762        77.673    3444586.024    0.809        0.809 
## V21           1    71275.834        46.678    3444617.019    0.809        0.809 
## V33           1    71275.873        29.968    3444633.729    0.809        0.809 
## V50           1    71275.915        11.798    3444651.899    0.809        0.809 
## V43           1    71275.918        10.376    3444653.321    0.809        0.809 
## V22           1    71275.937         2.150    3444661.547    0.809        0.809 
## V31           1    71275.938         1.823    3444661.874    0.809        0.809 
## V34           1    71275.940         1.266    3444662.431    0.809        0.809 
## V25           1    71275.942         0.002    3444663.695    0.809        0.809 
## -------------------------------------------------------------------------------
## 
## - V4 
## 
## 
##  Step 16 : AIC = 69508.38 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 + V12 + V19 + V10 + V3 + V13 + V8 + V4 
## 
## -------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq          RSS        R-Sq     Adj. R-Sq 
## -------------------------------------------------------------------------------
## V18           1    67262.095    676526.525    2085421.201    0.884        0.884 
## V9            1    67285.194    670497.941    2091449.785    0.884        0.884 
## V17           1    67386.735    643789.603    2118158.123    0.883        0.882 
## V11           1    67451.364    626612.736    2135334.990    0.882        0.881 
## V2            1    69427.104     28594.131    2733353.595    0.848        0.848 
## V40           1    69506.044      1495.839    2760451.887    0.847        0.847 
## V42           1    69507.003      1165.196    2760782.531    0.847        0.847 
## V1            1    69507.594       961.293    2760986.434    0.847        0.847 
## V27           1    69508.298       718.236    2761229.490    0.847        0.847 
## V44           1    69508.468       659.666    2761288.060    0.847        0.847 
## V48           1    69508.501       648.424    2761299.302    0.847        0.847 
## V24           1    69508.589       617.894    2761329.833    0.847        0.847 
## V45           1    69508.629       604.080    2761343.646    0.847        0.847 
## V26           1    69508.778       552.633    2761395.093    0.847        0.847 
## V21           1    69509.093       444.041    2761503.686    0.847        0.847 
## V41           1    69509.101       441.330    2761506.396    0.847        0.847 
## V39           1    69509.163       419.945    2761527.782    0.847        0.847 
## V49           1    69509.346       356.670    2761591.056    0.847        0.847 
## V34           1    69509.526       294.548    2761653.178    0.847        0.847 
## V33           1    69509.955       146.417    2761801.310    0.847        0.847 
## V37           1    69509.980       137.973    2761809.753    0.847        0.847 
## V32           1    69510.032       119.856    2761827.870    0.847        0.847 
## V28           1    69510.040       117.078    2761830.649    0.847        0.847 
## V50           1    69510.102        95.716    2761852.011    0.847        0.847 
## V43           1    69510.193        64.361    2761883.365    0.847        0.847 
## V23           1    69510.224        53.540    2761894.187    0.847        0.847 
## V29           1    69510.265        39.452    2761908.275    0.847        0.847 
## V30           1    69510.283        33.225    2761914.501    0.847        0.847 
## V22           1    69510.311        23.673    2761924.053    0.847        0.847 
## V35           1    69510.333        16.048    2761931.679    0.847        0.847 
## V47           1    69510.353         9.240    2761938.487    0.847        0.847 
## V36           1    69510.363         5.684    2761942.042    0.847        0.847 
## V25           1    69510.375         1.430    2761946.296    0.847        0.847 
## V46           1    69510.379         0.268    2761947.459    0.847        0.847 
## V31           1    69510.379         0.139    2761947.587    0.847        0.847 
## V38           1    69510.379         0.113    2761947.613    0.847        0.847 
## -------------------------------------------------------------------------------
## 
## - V18 
## 
## 
##  Step 17 : AIC = 67262.1 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 + V12 + V19 + V10 + V3 + V13 + V8 + V4 + V18 
## 
## -------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq          RSS        R-Sq     Adj. R-Sq 
## -------------------------------------------------------------------------------
## V9            1    64128.980    675999.702    1409421.499    0.922        0.922 
## V17           1    64228.065    658438.965    1426982.236    0.921        0.921 
## V11           1    64398.119    627789.014    1457632.187    0.919        0.919 
## V2            1    67138.363     32511.337    2052909.865    0.886        0.886 
## V40           1    67257.256      1781.752    2083639.450    0.884        0.884 
## V1            1    67260.751       871.379    2084549.822    0.884        0.884 
## V26           1    67261.729       616.682    2084804.519    0.884        0.884 
## V24           1    67261.997       546.686    2084874.515    0.884        0.884 
## V27           1    67262.201       493.743    2084927.459    0.884        0.884 
## V45           1    67262.493       417.505    2085003.696    0.884        0.884 
## V23           1    67262.576       395.996    2085025.205    0.884        0.884 
## V34           1    67262.763       347.145    2085074.056    0.884        0.884 
## V39           1    67262.871       318.935    2085102.267    0.884        0.884 
## V48           1    67263.156       244.785    2085176.416    0.884        0.884 
## V21           1    67263.212       230.130    2085191.072    0.884        0.884 
## V37           1    67263.265       216.254    2085204.947    0.884        0.884 
## V49           1    67263.467       163.802    2085257.400    0.884        0.884 
## V42           1    67263.482       159.748    2085261.453    0.884        0.884 
## V25           1    67263.515       151.282    2085269.920    0.884        0.884 
## V41           1    67263.720        97.850    2085323.352    0.884        0.884 
## V44           1    67263.758        87.871    2085333.331    0.884        0.884 
## V35           1    67263.764        86.434    2085334.767    0.884        0.884 
## V31           1    67263.765        86.004    2085335.197    0.884        0.884 
## V50           1    67263.777        82.921    2085338.281    0.884        0.884 
## V30           1    67263.805        75.687    2085345.515    0.884        0.884 
## V47           1    67263.877        56.771    2085364.431    0.884        0.884 
## V28           1    67263.945        39.130    2085382.071    0.884        0.884 
## V43           1    67263.982        29.591    2085391.610    0.884        0.884 
## V29           1    67264.040        14.462    2085406.739    0.884        0.884 
## V46           1    67264.054        10.850    2085410.351    0.884        0.884 
## V38           1    67264.059         9.374    2085411.827    0.884        0.884 
## V32           1    67264.075         5.274    2085415.927    0.884        0.884 
## V36           1    67264.090         1.265    2085419.937    0.884        0.884 
## V33           1    67264.092         0.981    2085420.220    0.884        0.884 
## V22           1    67264.095         0.090    2085421.111    0.884        0.884 
## -------------------------------------------------------------------------------
## 
## - V9 
## 
## 
##  Step 18 : AIC = 64128.98 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 + V12 + V19 + V10 + V3 + V13 + V8 + V4 + V18 + V9 
## 
## -------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq          RSS        R-Sq     Adj. R-Sq 
## -------------------------------------------------------------------------------
## V17           1    58972.904    669653.731     739767.768    0.959        0.959 
## V11           1    58973.772    669573.491     739848.007    0.959        0.959 
## V2            1    63951.273     31299.535    1378121.964    0.924        0.923 
## V1            1    64123.939      1239.488    1408182.011    0.922        0.922 
## V24           1    64126.096       859.985    1408561.514    0.922        0.922 
## V27           1    64127.531       607.306    1408814.193    0.922        0.922 
## V45           1    64127.745       569.634    1408851.864    0.922        0.922 
## V40           1    64127.792       561.325    1408860.174    0.922        0.922 
## V34           1    64128.066       513.028    1408908.471    0.922        0.922 
## V37           1    64129.057       338.593    1409082.906    0.922        0.922 
## V26           1    64129.380       281.736    1409139.763    0.922        0.922 
## V31           1    64129.711       223.420    1409198.078    0.922        0.922 
## V49           1    64129.844       199.956    1409221.542    0.922        0.922 
## V47           1    64129.893       191.372    1409230.127    0.922        0.922 
## V50           1    64130.310       118.010    1409303.489    0.922        0.922 
## V21           1    64130.428        97.194    1409324.305    0.922        0.922 
## V41           1    64130.471        89.539    1409331.960    0.922        0.922 
## V38           1    64130.477        88.586    1409332.913    0.922        0.922 
## V39           1    64130.599        67.003    1409354.496    0.922        0.922 
## V43           1    64130.674        53.825    1409367.674    0.922        0.922 
## V30           1    64130.686        51.699    1409369.799    0.922        0.922 
## V32           1    64130.694        50.229    1409371.270    0.922        0.922 
## V36           1    64130.785        34.265    1409387.234    0.922        0.922 
## V23           1    64130.859        21.291    1409400.208    0.922        0.922 
## V35           1    64130.860        21.066    1409400.433    0.922        0.922 
## V44           1    64130.868        19.656    1409401.843    0.922        0.922 
## V42           1    64130.886        16.552    1409404.947    0.922        0.922 
## V25           1    64130.894        15.165    1409406.334    0.922        0.922 
## V48           1    64130.896        14.684    1409406.815    0.922        0.922 
## V28           1    64130.899        14.253    1409407.245    0.922        0.922 
## V29           1    64130.955         4.304    1409417.195    0.922        0.922 
## V46           1    64130.965         2.489    1409419.010    0.922        0.922 
## V22           1    64130.978         0.351    1409421.148    0.922        0.922 
## V33           1    64130.979         0.019    1409421.480    0.922        0.922 
## -------------------------------------------------------------------------------
## 
## - V17 
## 
## 
##  Step 19 : AIC = 58972.9 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 + V12 + V19 + V10 + V3 + V13 + V8 + V4 + V18 + V9 + V17 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V11           1    37293.052    690524.032     49243.736    0.997        0.997 
## V2            1    58656.589     28849.958    710917.810    0.961        0.960 
## V1            1    58953.931      1936.351    737831.417    0.959        0.959 
## V45           1    58967.389       694.427    739073.341    0.959        0.959 
## V24           1    58969.378       510.643    739257.125    0.959        0.959 
## V40           1    58971.356       327.952    739439.816    0.959        0.959 
## V31           1    58971.698       296.332    739471.436    0.959        0.959 
## V33           1    58972.577       215.111    739552.657    0.959        0.959 
## V46           1    58972.881       186.980    739580.788    0.959        0.959 
## V21           1    58972.928       182.611    739585.157    0.959        0.959 
## V37           1    58973.035       172.762    739595.006    0.959        0.959 
## V41           1    58973.158       161.429    739606.339    0.959        0.959 
## V22           1    58973.646       116.273    739651.495    0.959        0.959 
## V34           1    58973.730       108.551    739659.217    0.959        0.959 
## V25           1    58974.125        71.980    739695.788    0.959        0.959 
## V35           1    58974.235        61.843    739705.925    0.959        0.959 
## V27           1    58974.306        55.324    739712.444    0.959        0.959 
## V38           1    58974.501        37.297    739730.471    0.959        0.959 
## V29           1    58974.504        37.001    739730.767    0.959        0.959 
## V28           1    58974.637        24.715    739743.053    0.959        0.959 
## V48           1    58974.655        22.991    739744.777    0.959        0.959 
## V44           1    58974.679        20.808    739746.960    0.959        0.959 
## V23           1    58974.686        20.106    739747.662    0.959        0.959 
## V39           1    58974.835         6.347    739761.421    0.959        0.959 
## V43           1    58974.840         5.902    739761.866    0.959        0.959 
## V42           1    58974.850         4.999    739762.769    0.959        0.959 
## V36           1    58974.859         4.143    739763.625    0.959        0.959 
## V26           1    58974.867         3.437    739764.331    0.959        0.959 
## V49           1    58974.874         2.780    739764.988    0.959        0.959 
## V32           1    58974.884         1.858    739765.910    0.959        0.959 
## V47           1    58974.901         0.277    739767.491    0.959        0.959 
## V30           1    58974.903         0.080    739767.688    0.959        0.959 
## V50           1    58974.904         0.011    739767.757    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V11 
## 
## 
##  Step 20 : AIC = 37293.05 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 + V12 + V19 + V10 + V3 + V13 + V8 + V4 + V18 + V9 + V17 + V11 
## 
## ----------------------------------------------------------------------------
## Variable     DF       AIC        Sum Sq         RSS       R-Sq     Adj. R-Sq 
## ----------------------------------------------------------------------------
## V2            1    28850.433    32102.815    17140.921    0.999        0.999 
## V1            1    36712.859     3455.543    45788.193    0.997        0.997 
## V39           1    37290.095       30.495    49213.241    0.997        0.997 
## V38           1    37293.478        9.686    49234.050    0.997        0.997 
## V47           1    37293.579        9.064    49234.672    0.997        0.997 
## V26           1    37293.811        7.633    49236.104    0.997        0.997 
## V46           1    37293.922        6.955    49236.782    0.997        0.997 
## V50           1    37294.233        5.038    49238.699    0.997        0.997 
## V28           1    37294.275        4.778    49238.958    0.997        0.997 
## V24           1    37294.307        4.584    49239.153    0.997        0.997 
## V43           1    37294.341        4.373    49239.363    0.997        0.997 
## V35           1    37294.372        4.182    49239.555    0.997        0.997 
## V41           1    37294.391        4.069    49239.667    0.997        0.997 
## V42           1    37294.475        3.552    49240.185    0.997        0.997 
## V49           1    37294.533        3.191    49240.546    0.997        0.997 
## V44           1    37294.820        1.425    49242.312    0.997        0.997 
## V34           1    37294.841        1.300    49242.436    0.997        0.997 
## V25           1    37294.854        1.219    49242.517    0.997        0.997 
## V22           1    37294.867        1.138    49242.599    0.997        0.997 
## V31           1    37294.882        1.044    49242.692    0.997        0.997 
## V45           1    37294.885        1.025    49242.711    0.997        0.997 
## V27           1    37294.894        0.969    49242.767    0.997        0.997 
## V21           1    37294.977        0.462    49243.274    0.997        0.997 
## V33           1    37294.987        0.401    49243.335    0.997        0.997 
## V40           1    37294.992        0.365    49243.371    0.997        0.997 
## V23           1    37295.019        0.200    49243.536    0.997        0.997 
## V29           1    37295.019        0.199    49243.537    0.997        0.997 
## V37           1    37295.027        0.155    49243.582    0.997        0.997 
## V30           1    37295.029        0.142    49243.594    0.997        0.997 
## V36           1    37295.040        0.070    49243.666    0.997        0.997 
## V32           1    37295.050        0.013    49243.723    0.997        0.997 
## V48           1    37295.051        0.004    49243.733    0.997        0.997 
## ----------------------------------------------------------------------------
## 
## - V2 
## 
## 
##  Step 21 : AIC = 28850.43 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 + V12 + V19 + V10 + V3 + V13 + V8 + V4 + V18 + V9 + V17 + V11 + V2 
## 
## ---------------------------------------------------------------------------
## Variable     DF       AIC        Sum Sq        RSS       R-Sq     Adj. R-Sq 
## ---------------------------------------------------------------------------
## V1            1    22088.480    9779.994     7360.927    1.000        1.000 
## V33           1    28849.418       6.456    17134.465    0.999        0.999 
## V49           1    28850.280       4.610    17136.311    0.999        0.999 
## V37           1    28850.319       4.527    17136.394    0.999        0.999 
## V38           1    28850.458       4.230    17136.691    0.999        0.999 
## V39           1    28851.393       2.227    17138.694    0.999        0.999 
## V23           1    28851.465       2.072    17138.849    0.999        0.999 
## V22           1    28851.469       2.064    17138.857    0.999        0.999 
## V24           1    28851.719       1.530    17139.391    0.999        0.999 
## V34           1    28851.811       1.333    17139.588    0.999        0.999 
## V50           1    28851.930       1.077    17139.844    0.999        0.999 
## V45           1    28851.936       1.064    17139.856    0.999        0.999 
## V40           1    28851.963       1.006    17139.915    0.999        0.999 
## V42           1    28852.139       0.629    17140.292    0.999        0.999 
## V47           1    28852.185       0.530    17140.391    0.999        0.999 
## V36           1    28852.211       0.475    17140.446    0.999        0.999 
## V35           1    28852.218       0.461    17140.460    0.999        0.999 
## V27           1    28852.240       0.414    17140.507    0.999        0.999 
## V21           1    28852.250       0.391    17140.530    0.999        0.999 
## V44           1    28852.275       0.339    17140.582    0.999        0.999 
## V43           1    28852.290       0.307    17140.614    0.999        0.999 
## V29           1    28852.326       0.229    17140.692    0.999        0.999 
## V26           1    28852.366       0.142    17140.779    0.999        0.999 
## V32           1    28852.406       0.059    17140.862    0.999        0.999 
## V28           1    28852.407       0.056    17140.864    0.999        0.999 
## V25           1    28852.418       0.031    17140.890    0.999        0.999 
## V48           1    28852.420       0.028    17140.893    0.999        0.999 
## V46           1    28852.429       0.008    17140.913    0.999        0.999 
## V41           1    28852.432       0.003    17140.918    0.999        0.999 
## V31           1    28852.432       0.002    17140.919    0.999        0.999 
## V30           1    28852.433       0.000    17140.921    0.999        0.999 
## ---------------------------------------------------------------------------
## 
## - V1 
## 
## 
##  Step 22 : AIC = 22088.48 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 + V12 + V19 + V10 + V3 + V13 + V8 + V4 + V18 + V9 + V17 + V11 + V2 + V1 
## 
## ------------------------------------------------------------------------
## Variable     DF       AIC       Sum Sq      RSS       R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------
## V37           1    22084.832     5.194    7355.733    1.000        1.000 
## V27           1    22085.352     4.715    7356.212    1.000        1.000 
## V24           1    22088.302     2.003    7358.924    1.000        1.000 
## V42           1    22088.372     1.939    7358.988    1.000        1.000 
## V33           1    22088.974     1.385    7359.542    1.000        1.000 
## V47           1    22089.427     0.969    7359.958    1.000        1.000 
## V36           1    22089.480     0.920    7360.007    1.000        1.000 
## V50           1    22089.650     0.764    7360.163    1.000        1.000 
## V44           1    22089.777     0.646    7360.280    1.000        1.000 
## V49           1    22089.832     0.596    7360.331    1.000        1.000 
## V22           1    22089.937     0.499    7360.428    1.000        1.000 
## V29           1    22089.995     0.446    7360.481    1.000        1.000 
## V21           1    22090.030     0.414    7360.513    1.000        1.000 
## V35           1    22090.073     0.375    7360.552    1.000        1.000 
## V45           1    22090.201     0.257    7360.670    1.000        1.000 
## V30           1    22090.242     0.219    7360.708    1.000        1.000 
## V25           1    22090.293     0.172    7360.754    1.000        1.000 
## V43           1    22090.332     0.136    7360.791    1.000        1.000 
## V23           1    22090.335     0.134    7360.793    1.000        1.000 
## V39           1    22090.342     0.127    7360.800    1.000        1.000 
## V48           1    22090.344     0.125    7360.802    1.000        1.000 
## V38           1    22090.366     0.105    7360.822    1.000        1.000 
## V34           1    22090.385     0.087    7360.840    1.000        1.000 
## V28           1    22090.411     0.063    7360.864    1.000        1.000 
## V41           1    22090.414     0.061    7360.866    1.000        1.000 
## V46           1    22090.418     0.057    7360.870    1.000        1.000 
## V31           1    22090.436     0.040    7360.887    1.000        1.000 
## V26           1    22090.473     0.007    7360.920    1.000        1.000 
## V32           1    22090.475     0.005    7360.922    1.000        1.000 
## V40           1    22090.474     0.005    7360.922    1.000        1.000 
## ------------------------------------------------------------------------
## 
## - V37 
## 
## 
##  Step 23 : AIC = 22084.83 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 + V12 + V19 + V10 + V3 + V13 + V8 + V4 + V18 + V9 + V17 + V11 + V2 + V1 + V37 
## 
## ------------------------------------------------------------------------
## Variable     DF       AIC       Sum Sq      RSS       R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------
## V27           1    22081.609     4.800    7350.934    1.000        1.000 
## V24           1    22084.597     2.054    7353.679    1.000        1.000 
## V42           1    22084.667     1.990    7353.743    1.000        1.000 
## V33           1    22085.237     1.466    7354.267    1.000        1.000 
## V36           1    22085.801     0.947    7354.786    1.000        1.000 
## V47           1    22085.814     0.936    7354.797    1.000        1.000 
## V50           1    22086.011     0.755    7354.978    1.000        1.000 
## V44           1    22086.156     0.622    7355.112    1.000        1.000 
## V49           1    22086.229     0.554    7355.179    1.000        1.000 
## V22           1    22086.284     0.504    7355.229    1.000        1.000 
## V29           1    22086.346     0.446    7355.287    1.000        1.000 
## V21           1    22086.359     0.435    7355.298    1.000        1.000 
## V35           1    22086.422     0.377    7355.357    1.000        1.000 
## V45           1    22086.500     0.305    7355.428    1.000        1.000 
## V30           1    22086.600     0.213    7355.520    1.000        1.000 
## V25           1    22086.633     0.183    7355.550    1.000        1.000 
## V48           1    22086.655     0.163    7355.570    1.000        1.000 
## V43           1    22086.677     0.143    7355.590    1.000        1.000 
## V39           1    22086.678     0.142    7355.592    1.000        1.000 
## V23           1    22086.709     0.113    7355.620    1.000        1.000 
## V38           1    22086.718     0.105    7355.629    1.000        1.000 
## V34           1    22086.743     0.082    7355.651    1.000        1.000 
## V46           1    22086.768     0.059    7355.674    1.000        1.000 
## V31           1    22086.778     0.050    7355.684    1.000        1.000 
## V41           1    22086.778     0.050    7355.683    1.000        1.000 
## V28           1    22086.788     0.040    7355.693    1.000        1.000 
## V26           1    22086.818     0.013    7355.721    1.000        1.000 
## V40           1    22086.822     0.009    7355.724    1.000        1.000 
## V32           1    22086.832     0.000    7355.733    1.000        1.000 
## ------------------------------------------------------------------------
## 
## - V27 
## 
## 
##  Step 24 : AIC = 22081.61 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 + V12 + V19 + V10 + V3 + V13 + V8 + V4 + V18 + V9 + V17 + V11 + V2 + V1 + V37 + V27 
## 
## ------------------------------------------------------------------------
## Variable     DF       AIC       Sum Sq      RSS       R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------
## V42           1    22081.466     1.969    7348.965    1.000        1.000 
## V24           1    22081.467     1.968    7348.966    1.000        1.000 
## V33           1    22081.925     1.547    7349.386    1.000        1.000 
## V36           1    22082.531     0.991    7349.943    1.000        1.000 
## V47           1    22082.633     0.897    7350.037    1.000        1.000 
## V50           1    22082.769     0.771    7350.162    1.000        1.000 
## V44           1    22082.931     0.623    7350.311    1.000        1.000 
## V49           1    22083.024     0.537    7350.396    1.000        1.000 
## V22           1    22083.063     0.502    7350.432    1.000        1.000 
## V29           1    22083.114     0.455    7350.479    1.000        1.000 
## V21           1    22083.134     0.436    7350.497    1.000        1.000 
## V35           1    22083.192     0.383    7350.551    1.000        1.000 
## V45           1    22083.253     0.327    7350.607    1.000        1.000 
## V30           1    22083.380     0.211    7350.723    1.000        1.000 
## V25           1    22083.418     0.176    7350.758    1.000        1.000 
## V43           1    22083.426     0.168    7350.766    1.000        1.000 
## V39           1    22083.439     0.157    7350.777    1.000        1.000 
## V48           1    22083.442     0.154    7350.780    1.000        1.000 
## V23           1    22083.488     0.111    7350.823    1.000        1.000 
## V38           1    22083.489     0.110    7350.823    1.000        1.000 
## V34           1    22083.533     0.069    7350.864    1.000        1.000 
## V31           1    22083.548     0.056    7350.877    1.000        1.000 
## V41           1    22083.551     0.053    7350.880    1.000        1.000 
## V28           1    22083.560     0.045    7350.889    1.000        1.000 
## V46           1    22083.563     0.042    7350.891    1.000        1.000 
## V40           1    22083.592     0.016    7350.917    1.000        1.000 
## V26           1    22083.607     0.002    7350.931    1.000        1.000 
## V32           1    22083.609     0.000    7350.933    1.000        1.000 
## ------------------------------------------------------------------------
## 
## - V42 
## 
## 
##  Step 25 : AIC = 22081.47 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 + V12 + V19 + V10 + V3 + V13 + V8 + V4 + V18 + V9 + V17 + V11 + V2 + V1 + V37 + V27 + V42 
## 
## ------------------------------------------------------------------------
## Variable     DF       AIC       Sum Sq      RSS       R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------
## V24           1    22081.363     1.931    7347.034    1.000        1.000 
## V33           1    22081.818     1.513    7347.452    1.000        1.000 
## V36           1    22082.383     0.994    7347.971    1.000        1.000 
## V47           1    22082.473     0.912    7348.053    1.000        1.000 
## V50           1    22082.620     0.777    7348.188    1.000        1.000 
## V44           1    22082.758     0.650    7348.315    1.000        1.000 
## V49           1    22082.888     0.531    7348.434    1.000        1.000 
## V22           1    22082.922     0.499    7348.466    1.000        1.000 
## V21           1    22082.981     0.445    7348.520    1.000        1.000 
## V29           1    22082.989     0.438    7348.527    1.000        1.000 
## V35           1    22083.044     0.387    7348.578    1.000        1.000 
## V45           1    22083.113     0.324    7348.641    1.000        1.000 
## V30           1    22083.226     0.220    7348.745    1.000        1.000 
## V43           1    22083.280     0.170    7348.795    1.000        1.000 
## V25           1    22083.285     0.166    7348.799    1.000        1.000 
## V48           1    22083.302     0.151    7348.814    1.000        1.000 
## V39           1    22083.305     0.148    7348.817    1.000        1.000 
## V38           1    22083.344     0.111    7348.854    1.000        1.000 
## V23           1    22083.348     0.108    7348.857    1.000        1.000 
## V34           1    22083.386     0.073    7348.892    1.000        1.000 
## V31           1    22083.400     0.060    7348.905    1.000        1.000 
## V41           1    22083.405     0.056    7348.909    1.000        1.000 
## V28           1    22083.408     0.053    7348.912    1.000        1.000 
## V46           1    22083.432     0.031    7348.934    1.000        1.000 
## V40           1    22083.451     0.013    7348.952    1.000        1.000 
## V26           1    22083.463     0.002    7348.963    1.000        1.000 
## V32           1    22083.466     0.000    7348.965    1.000        1.000 
## ------------------------------------------------------------------------
## 
## - V24 
## 
## 
##  Step 26 : AIC = 22081.36 
##  Y ~ V51 + V52 + V15 + V20 + V16 + V14 + V7 + V6 + V5 + V12 + V19 + V10 + V3 + V13 + V8 + V4 + V18 + V9 + V17 + V11 + V2 + V1 + V37 + V27 + V42 + V24 
## 
## ------------------------------------------------------------------------
## Variable     DF       AIC       Sum Sq      RSS       R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------
## V33           1    22081.708     1.519    7345.514    1.000        1.000 
## V36           1    22082.283     0.992    7346.042    1.000        1.000 
## V47           1    22082.340     0.939    7346.095    1.000        1.000 
## V50           1    22082.476     0.814    7346.220    1.000        1.000 
## V44           1    22082.616     0.686    7346.348    1.000        1.000 
## V22           1    22082.790     0.526    7346.508    1.000        1.000 
## V49           1    22082.827     0.492    7346.542    1.000        1.000 
## V21           1    22082.874     0.449    7346.585    1.000        1.000 
## V29           1    22082.875     0.448    7346.586    1.000        1.000 
## V35           1    22082.951     0.378    7346.656    1.000        1.000 
## V45           1    22083.010     0.324    7346.710    1.000        1.000 
## V43           1    22083.135     0.209    7346.824    1.000        1.000 
## V30           1    22083.162     0.185    7346.849    1.000        1.000 
## V25           1    22083.192     0.157    7346.877    1.000        1.000 
## V39           1    22083.201     0.148    7346.885    1.000        1.000 
## V48           1    22083.206     0.144    7346.890    1.000        1.000 
## V23           1    22083.229     0.123    7346.911    1.000        1.000 
## V38           1    22083.250     0.103    7346.930    1.000        1.000 
## V34           1    22083.280     0.076    7346.958    1.000        1.000 
## V28           1    22083.298     0.060    7346.974    1.000        1.000 
## V31           1    22083.302     0.056    7346.978    1.000        1.000 
## V41           1    22083.319     0.041    7346.993    1.000        1.000 
## V46           1    22083.331     0.029    7347.005    1.000        1.000 
## V40           1    22083.349     0.012    7347.022    1.000        1.000 
## V26           1    22083.355     0.007    7347.027    1.000        1.000 
## V32           1    22083.363     0.000    7347.034    1.000        1.000 
## ------------------------------------------------------------------------
## 
## 
## No more variables to be added.
## 
## Variables Entered: 
## 
## - V51 
## - V52 
## - V15 
## - V20 
## - V16 
## - V14 
## - V7 
## - V6 
## - V5 
## - V12 
## - V19 
## - V10 
## - V3 
## - V13 
## - V8 
## - V4 
## - V18 
## - V9 
## - V17 
## - V11 
## - V2 
## - V1 
## - V37 
## - V27 
## - V42 
## - V24 
## 
## 
## Final Model Output 
## ------------------
## 
##                         Model Summary                         
## -------------------------------------------------------------
## R                       1.000       RMSE               0.960 
## R-Squared               1.000       Coef. Var          0.190 
## Adj. R-Squared          1.000       MSE                0.921 
## Pred R-Squared          1.000       MAE                0.697 
## -------------------------------------------------------------
##  RMSE: Root Mean Square Error 
##  MSE: Mean Square Error 
##  MAE: Mean Absolute Error 
## 
##                                     ANOVA                                      
## ------------------------------------------------------------------------------
##                     Sum of                                                    
##                    Squares          DF    Mean Square        F           Sig. 
## ------------------------------------------------------------------------------
## Regression    18028630.897          26     693408.881    752675.962    0.0000 
## Residual          7347.034        7975          0.921                         
## Total         18035977.931        8001                                        
## ------------------------------------------------------------------------------
## 
##                                    Parameter Estimates                                     
## ------------------------------------------------------------------------------------------
##       model      Beta    Std. Error    Std. Beta       t         Sig      lower     upper 
## ------------------------------------------------------------------------------------------
## (Intercept)     2.601         0.185                   14.073    0.000     2.238     2.963 
##         V51    -4.488         0.010       -0.914    -462.952    0.000    -4.507    -4.469 
##         V52    -4.517         0.012       -0.193    -380.731    0.000    -4.540    -4.493 
##         V15     3.502         0.004        0.201     890.173    0.000     3.494     3.510 
##         V20     3.495         0.004        0.201     887.889    0.000     3.488     3.503 
##         V16     3.501         0.004        0.202     891.642    0.000     3.494     3.509 
##         V14     3.501         0.004        0.201     889.322    0.000     3.493     3.508 
##          V7     3.506         0.004        0.201     887.362    0.000     3.498     3.513 
##          V6     3.500         0.004        0.200     883.180    0.000     3.493     3.508 
##          V5     3.502         0.004        0.202     894.446    0.000     3.495     3.510 
##         V12     3.509         0.004        0.199     876.929    0.000     3.501     3.516 
##         V19     3.502         0.004        0.200     883.324    0.000     3.495     3.510 
##         V10     3.496         0.004        0.199     880.979    0.000     3.488     3.504 
##          V3     3.493         0.004        0.201     887.386    0.000     3.485     3.501 
##         V13     3.499         0.004        0.201     890.018    0.000     3.492     3.507 
##          V8     3.498         0.004        0.201     887.750    0.000     3.490     3.506 
##          V4     3.494         0.004        0.197     872.963    0.000     3.487     3.502 
##         V18     3.505         0.004        0.198     873.053    0.000     3.497     3.513 
##          V9     3.500         0.004        0.202     890.071    0.000     3.492     3.507 
##         V17     3.491         0.004        0.196     864.819    0.000     3.483     3.499 
##         V11     3.501         0.004        0.197     869.336    0.000     3.493     3.509 
##          V2     3.496         0.017        0.157     204.239    0.000     3.462     3.529 
##          V1     3.449         0.033        0.199     103.069    0.000     3.383     3.514 
##         V37    -0.009         0.004       -0.001      -2.416    0.016    -0.017    -0.002 
##         V27    -0.009         0.004       -0.001      -2.257    0.024    -0.017    -0.001 
##         V42    -0.006         0.004        0.000      -1.448    0.148    -0.014     0.002 
##         V24    -0.006         0.004        0.000      -1.448    0.148    -0.014     0.002 
## ------------------------------------------------------------------------------------------
mod_forwd
## 
##                               Selection Summary                                
## ------------------------------------------------------------------------------
## Variable        AIC          Sum Sq           RSS          R-Sq      Adj. R-Sq 
## ------------------------------------------------------------------------------
## V51          82368.667     4206265.441    13829712.490    0.23322      0.23312 
## V52          81673.595     5360020.059    12675957.872    0.29718      0.29701 
## V15          81164.271     6144671.263    11891306.668    0.34069      0.34044 
## V20          80643.109     6897242.453    11138735.478    0.38242      0.38211 
## V16          80091.127     7642294.607    10393683.324    0.42372      0.42336 
## V14          79524.715     8354984.409     9680993.521    0.46324      0.46284 
## V7           78907.750     9075592.575     8960385.356    0.50319      0.50276 
## V6           78258.066     9776403.744     8259574.187    0.54205      0.54159 
## V5           77566.468    10462177.766     7573800.165    0.58007      0.57960 
## V12          76819.889    11138567.445     6897410.486    0.61757      0.61710 
## V19          75959.278    11843430.042     6192547.889    0.65666      0.65618 
## V10          75009.700    12537732.163     5498245.768    0.69515      0.69469 
## V3           73942.448    13225453.930     4810524.001    0.73328      0.73285 
## V13          72717.194    13909445.030     4126532.901    0.77121      0.77080 
## V8           71273.942    14591314.234     3444663.697    0.80901      0.80865 
## V4           69508.379    15274030.204     2761947.726    0.84686      0.84656 
## V18          67262.095    15950556.729     2085421.201    0.88437      0.88413 
## V9           64128.980    16626556.432     1409421.499    0.92185      0.92168 
## V17          58972.904    17296210.163      739767.768    0.95898      0.95889 
## V11          37293.052    17986734.194       49243.736    0.99727      0.99726 
## V2           28850.433    18018837.010       17140.921    0.99905      0.99905 
## V1           22088.480    18028617.004        7360.927    0.99959      0.99959 
## V37          22084.832    18028622.197        7355.733    0.99959      0.99959 
## V27          22081.609    18028626.997        7350.934    0.99959      0.99959 
## V42          22081.466    18028628.966        7348.965    0.99959      0.99959 
## V24          22081.363    18028630.897        7347.034    0.99959      0.99959 
## ------------------------------------------------------------------------------
mod_forwd$model
## 
## Call:
## lm(formula = paste(response, "~", paste(preds, collapse = " + ")), 
##     data = l)
## 
## Coefficients:
## (Intercept)          V51          V52          V15          V20          V16  
##    2.600549    -4.487634    -4.516698     3.501821     3.495246     3.501314  
##         V14           V7           V6           V5          V12          V19  
##    3.500580     3.505625     3.500391     3.502448     3.508631     3.502441  
##         V10           V3          V13           V8           V4          V18  
##    3.495768     3.493128     3.499304     3.497991     3.494456     3.505106  
##          V9          V17          V11           V2           V1          V37  
##    3.499672     3.491392     3.501190     3.495759     3.448787    -0.009406  
##         V27          V42          V24  
##   -0.008911    -0.005739    -0.005822
#Backward Selection
mod_bcwd<- ols_step_backward_aic(Mod_best, prem = 0.1, details = T  )
## Backward Elimination Method 
## ---------------------------
## 
## Candidate Terms: 
## 
## 1 . V1 
## 2 . V2 
## 3 . V3 
## 4 . V4 
## 5 . V5 
## 6 . V6 
## 7 . V7 
## 8 . V8 
## 9 . V9 
## 10 . V10 
## 11 . V11 
## 12 . V12 
## 13 . V13 
## 14 . V14 
## 15 . V15 
## 16 . V16 
## 17 . V17 
## 18 . V18 
## 19 . V19 
## 20 . V20 
## 21 . V21 
## 22 . V22 
## 23 . V23 
## 24 . V24 
## 25 . V25 
## 26 . V26 
## 27 . V27 
## 28 . V28 
## 29 . V29 
## 30 . V30 
## 31 . V31 
## 32 . V32 
## 33 . V33 
## 34 . V34 
## 35 . V35 
## 36 . V36 
## 37 . V37 
## 38 . V38 
## 39 . V39 
## 40 . V40 
## 41 . V41 
## 42 . V42 
## 43 . V43 
## 44 . V44 
## 45 . V45 
## 46 . V46 
## 47 . V47 
## 48 . V48 
## 49 . V49 
## 50 . V50 
## 51 . V51 
## 52 . V52 
## 
##  Step 0: AIC = 22123.58 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V23 + V24 + V25 + V26 + V27 + V28 + V29 + V30 + V31 + V32 + V33 + V34 + V35 + V36 + V37 + V38 + V39 + V40 + V41 + V42 + V43 + V44 + V45 + V46 + V47 + V48 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V32          1     22121.582         0.001      7338.059    1.000        1.000 
## V26          1     22121.585         0.003      7338.062    1.000        1.000 
## V40          1     22121.599         0.015      7338.074    1.000        1.000 
## V46          1     22121.610         0.026      7338.085    1.000        1.000 
## V41          1     22121.633         0.047      7338.106    1.000        1.000 
## V28          1     22121.637         0.051      7338.110    1.000        1.000 
## V31          1     22121.642         0.056      7338.114    1.000        1.000 
## V34          1     22121.644         0.057      7338.116    1.000        1.000 
## V39          1     22121.718         0.125      7338.184    1.000        1.000 
## V38          1     22121.719         0.126      7338.185    1.000        1.000 
## V23          1     22121.726         0.132      7338.191    1.000        1.000 
## V48          1     22121.740         0.145      7338.204    1.000        1.000 
## V25          1     22121.814         0.213      7338.272    1.000        1.000 
## V30          1     22121.818         0.217      7338.276    1.000        1.000 
## V43          1     22121.854         0.249      7338.308    1.000        1.000 
## V45          1     22121.904         0.296      7338.355    1.000        1.000 
## V29          1     22122.010         0.393      7338.452    1.000        1.000 
## V35          1     22122.043         0.423      7338.482    1.000        1.000 
## V21          1     22122.052         0.431      7338.490    1.000        1.000 
## V49          1     22122.134         0.506      7338.565    1.000        1.000 
## V22          1     22122.150         0.521      7338.580    1.000        1.000 
## V44          1     22122.264         0.625      7338.684    1.000        1.000 
## V47          1     22122.539         0.878      7338.937    1.000        1.000 
## V50          1     22122.553         0.891      7338.950    1.000        1.000 
## V36          1     22122.763         1.084      7339.142    1.000        1.000 
## V33          1     22123.234         1.515      7339.574    1.000        1.000 
## V42          1     22123.681         1.925      7339.984    1.000        1.000 
## V24          1     22123.768         2.005      7340.064    1.000        1.000 
## V27          1     22126.845         4.828      7342.887    1.000        1.000 
## V37          1     22127.556         5.481      7343.539    1.000        1.000 
## V1           1     28893.224      9766.039     17104.098    0.999        0.999 
## V2           1     36751.035     38325.424     45663.483    0.997        0.997 
## V52          1     45748.430    133230.069    140568.128    0.992        0.992 
## V51          1     48744.162    197059.123    204397.182    0.989        0.989 
## V17          1     58525.256    686609.454    693947.513    0.962        0.961 
## V11          1     58606.753    693713.118    701051.177    0.961        0.961 
## V4           1     58673.698    699602.753    706940.812    0.961        0.961 
## V18          1     58686.140    700702.743    708040.802    0.961        0.960 
## V12          1     58748.440    706236.807    713574.865    0.960        0.960 
## V10          1     58821.987    712825.515    720163.574    0.960        0.960 
## V6           1     58858.816    716147.696    723485.755    0.960        0.960 
## V19          1     58867.300    716915.148    724253.207    0.960        0.960 
## V20          1     58923.778    722044.992    729383.051    0.960        0.959 
## V3           1     58935.524    723116.470    730454.528    0.960        0.959 
## V7           1     58938.896    723424.373    730762.432    0.959        0.959 
## V8           1     58944.847    723968.049    731306.108    0.959        0.959 
## V14          1     58977.658    726972.766    734310.824    0.959        0.959 
## V13          1     58980.185    727204.703    734542.762    0.959        0.959 
## V9           1     58986.738    727806.453    735144.511    0.959        0.959 
## V15          1     58995.168    728581.322    735919.381    0.959        0.959 
## V16          1     59016.061    730505.288    737843.346    0.959        0.959 
## V5           1     59054.804    734086.375    741424.434    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## 
## Variables Removed: 
## 
## - V32 
## 
## 
##   Step 1 : AIC = 22121.58 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V23 + V24 + V25 + V26 + V27 + V28 + V29 + V30 + V31 + V33 + V34 + V35 + V36 + V37 + V38 + V39 + V40 + V41 + V42 + V43 + V44 + V45 + V46 + V47 + V48 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V26          1     22119.585         0.003      7338.062    1.000        1.000 
## V40          1     22119.599         0.016      7338.075    1.000        1.000 
## V46          1     22119.611         0.026      7338.086    1.000        1.000 
## V41          1     22119.634         0.047      7338.107    1.000        1.000 
## V28          1     22119.638         0.051      7338.111    1.000        1.000 
## V31          1     22119.643         0.056      7338.115    1.000        1.000 
## V34          1     22119.645         0.057      7338.117    1.000        1.000 
## V39          1     22119.719         0.125      7338.184    1.000        1.000 
## V38          1     22119.720         0.126      7338.186    1.000        1.000 
## V23          1     22119.726         0.132      7338.191    1.000        1.000 
## V48          1     22119.740         0.145      7338.204    1.000        1.000 
## V25          1     22119.814         0.213      7338.272    1.000        1.000 
## V30          1     22119.820         0.218      7338.277    1.000        1.000 
## V43          1     22119.854         0.249      7338.309    1.000        1.000 
## V45          1     22119.905         0.296      7338.355    1.000        1.000 
## V29          1     22120.010         0.393      7338.452    1.000        1.000 
## V35          1     22120.044         0.423      7338.483    1.000        1.000 
## V21          1     22120.052         0.430      7338.490    1.000        1.000 
## V49          1     22120.135         0.507      7338.566    1.000        1.000 
## V22          1     22120.150         0.521      7338.580    1.000        1.000 
## V44          1     22120.264         0.625      7338.685    1.000        1.000 
## V47          1     22120.539         0.878      7338.937    1.000        1.000 
## V50          1     22120.554         0.891      7338.950    1.000        1.000 
## V36          1     22120.763         1.083      7339.143    1.000        1.000 
## V33          1     22121.236         1.517      7339.576    1.000        1.000 
## V42          1     22121.683         1.926      7339.986    1.000        1.000 
## V24          1     22121.769         2.005      7340.065    1.000        1.000 
## V27          1     22124.845         4.828      7342.887    1.000        1.000 
## V37          1     22125.557         5.481      7343.541    1.000        1.000 
## V1           1     28891.252      9766.098     17104.158    0.999        0.999 
## V2           1     36749.041     38325.459     45663.518    0.997        0.997 
## V52          1     45746.698    133234.766    140572.826    0.992        0.992 
## V51          1     48742.179    197059.573    204397.633    0.989        0.989 
## V17          1     58523.646    686643.290    693981.350    0.962        0.961 
## V11          1     58604.781    693715.538    701053.597    0.961        0.961 
## V4           1     58674.120    699816.751    707154.811    0.961        0.961 
## V18          1     58686.056    700872.370    708210.430    0.961        0.960 
## V12          1     58746.522    706244.124    713582.184    0.960        0.960 
## V10          1     58820.771    712896.098    720234.157    0.960        0.960 
## V6           1     58857.607    716219.201    723557.261    0.960        0.960 
## V19          1     58866.163    716993.297    724331.357    0.960        0.960 
## V20          1     58923.283    722182.203    729520.263    0.960        0.959 
## V3           1     58936.939    723428.282    730766.341    0.959        0.959 
## V7           1     58937.477    723477.407    730815.466    0.959        0.959 
## V8           1     58944.945    724159.742    731497.801    0.959        0.959 
## V14          1     58976.039    727007.694    734345.754    0.959        0.959 
## V13          1     58978.186    727204.799    734542.858    0.959        0.959 
## V9           1     58984.924    727823.532    735161.592    0.959        0.959 
## V15          1     58993.179    728582.399    735920.459    0.959        0.959 
## V16          1     59014.160    730514.465    737852.525    0.959        0.959 
## V5           1     59057.835    734552.645    741890.704    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V26 
## 
## 
##   Step 2 : AIC = 22119.59 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V23 + V24 + V25 + V27 + V28 + V29 + V30 + V31 + V33 + V34 + V35 + V36 + V37 + V38 + V39 + V40 + V41 + V42 + V43 + V44 + V45 + V46 + V47 + V48 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V40          1     22117.602         0.016      7338.078    1.000        1.000 
## V46          1     22117.614         0.026      7338.089    1.000        1.000 
## V41          1     22117.636         0.047      7338.109    1.000        1.000 
## V28          1     22117.641         0.051      7338.113    1.000        1.000 
## V31          1     22117.646         0.055      7338.118    1.000        1.000 
## V34          1     22117.648         0.058      7338.120    1.000        1.000 
## V39          1     22117.722         0.125      7338.188    1.000        1.000 
## V38          1     22117.723         0.126      7338.188    1.000        1.000 
## V23          1     22117.729         0.132      7338.194    1.000        1.000 
## V48          1     22117.744         0.145      7338.208    1.000        1.000 
## V25          1     22117.819         0.214      7338.276    1.000        1.000 
## V30          1     22117.823         0.218      7338.280    1.000        1.000 
## V43          1     22117.857         0.249      7338.311    1.000        1.000 
## V45          1     22117.910         0.298      7338.360    1.000        1.000 
## V29          1     22118.014         0.393      7338.456    1.000        1.000 
## V35          1     22118.047         0.423      7338.485    1.000        1.000 
## V21          1     22118.053         0.429      7338.491    1.000        1.000 
## V49          1     22118.138         0.506      7338.569    1.000        1.000 
## V22          1     22118.155         0.523      7338.585    1.000        1.000 
## V44          1     22118.266         0.624      7338.686    1.000        1.000 
## V47          1     22118.543         0.878      7338.940    1.000        1.000 
## V50          1     22118.556         0.890      7338.952    1.000        1.000 
## V36          1     22118.767         1.084      7339.146    1.000        1.000 
## V33          1     22119.240         1.518      7339.580    1.000        1.000 
## V42          1     22119.685         1.926      7339.988    1.000        1.000 
## V24          1     22119.769         2.003      7340.065    1.000        1.000 
## V27          1     22122.860         4.839      7342.901    1.000        1.000 
## V37          1     22123.558         5.479      7343.541    1.000        1.000 
## V1           1     28889.313      9766.226     17104.289    0.999        0.999 
## V2           1     36748.358     38332.974     45671.036    0.997        0.997 
## V52          1     45746.759    133270.975    140609.037    0.992        0.992 
## V51          1     48740.407    197065.393    204403.456    0.989        0.989 
## V17          1     58525.278    686958.278    694296.340    0.962        0.961 
## V11          1     58602.984    693733.321    701071.384    0.961        0.961 
## V4           1     58672.171    699821.231    707159.294    0.961        0.961 
## V18          1     58684.063    700872.978    708211.040    0.961        0.960 
## V12          1     58744.538    706245.543    713583.606    0.960        0.960 
## V10          1     58820.034    713009.786    720347.848    0.960        0.960 
## V6           1     58855.641    716222.284    723560.346    0.960        0.960 
## V19          1     58864.477    717021.755    724359.817    0.960        0.960 
## V20          1     58921.285    722182.425    729520.487    0.960        0.959 
## V3           1     58935.312    723462.332    730800.395    0.959        0.959 
## V7           1     58936.862    723603.913    730941.976    0.959        0.959 
## V8           1     58942.989    724163.749    731501.811    0.959        0.959 
## V14          1     58974.990    727095.010    734433.073    0.959        0.959 
## V13          1     58976.535    727236.869    734574.931    0.959        0.959 
## V9           1     58983.801    727904.156    735242.218    0.959        0.959 
## V15          1     58991.882    728647.052    735985.114    0.959        0.959 
## V16          1     59012.458    730541.928    737879.990    0.959        0.959 
## V5           1     59060.056    734944.076    742282.138    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V40 
## 
## 
##   Step 3 : AIC = 22117.6 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V23 + V24 + V25 + V27 + V28 + V29 + V30 + V31 + V33 + V34 + V35 + V36 + V37 + V38 + V39 + V41 + V42 + V43 + V44 + V45 + V46 + V47 + V48 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V46          1     22115.632         0.027      7338.105    1.000        1.000 
## V41          1     22115.654         0.048      7338.125    1.000        1.000 
## V28          1     22115.658         0.051      7338.129    1.000        1.000 
## V31          1     22115.662         0.055      7338.133    1.000        1.000 
## V34          1     22115.666         0.058      7338.136    1.000        1.000 
## V38          1     22115.738         0.125      7338.203    1.000        1.000 
## V39          1     22115.740         0.126      7338.204    1.000        1.000 
## V23          1     22115.745         0.131      7338.209    1.000        1.000 
## V48          1     22115.762         0.146      7338.224    1.000        1.000 
## V25          1     22115.836         0.214      7338.292    1.000        1.000 
## V30          1     22115.839         0.217      7338.295    1.000        1.000 
## V43          1     22115.875         0.250      7338.328    1.000        1.000 
## V45          1     22115.929         0.299      7338.377    1.000        1.000 
## V29          1     22116.031         0.393      7338.471    1.000        1.000 
## V35          1     22116.065         0.425      7338.502    1.000        1.000 
## V21          1     22116.071         0.430      7338.507    1.000        1.000 
## V49          1     22116.154         0.506      7338.584    1.000        1.000 
## V22          1     22116.173         0.523      7338.601    1.000        1.000 
## V44          1     22116.281         0.622      7338.700    1.000        1.000 
## V47          1     22116.558         0.876      7338.954    1.000        1.000 
## V50          1     22116.572         0.889      7338.967    1.000        1.000 
## V36          1     22116.783         1.083      7339.160    1.000        1.000 
## V33          1     22117.256         1.516      7339.594    1.000        1.000 
## V42          1     22117.705         1.929      7340.006    1.000        1.000 
## V24          1     22117.787         2.004      7340.082    1.000        1.000 
## V27          1     22120.870         4.832      7342.910    1.000        1.000 
## V37          1     22121.569         5.474      7343.552    1.000        1.000 
## V1           1     28887.822      9767.299     17105.377    0.999        0.999 
## V2           1     36746.654     38334.643     45672.721    0.997        0.997 
## V52          1     45744.791    133271.517    140609.595    0.992        0.992 
## V51          1     48738.650    197071.586    204409.664    0.989        0.989 
## V17          1     58523.725    686997.087    694335.165    0.962        0.961 
## V11          1     58604.418    694034.215    701372.293    0.961        0.961 
## V4           1     58670.276    699830.492    707168.570    0.961        0.961 
## V18          1     58682.226    700887.386    708225.464    0.961        0.960 
## V12          1     58742.649    706255.407    713593.485    0.960        0.960 
## V10          1     58818.615    713062.115    720400.193    0.960        0.960 
## V6           1     58858.038    716619.945    723958.023    0.960        0.960 
## V19          1     58862.515    717025.143    724363.221    0.960        0.960 
## V20          1     58919.285    722182.410    729520.488    0.960        0.959 
## V3           1     58933.888    723514.913    730852.991    0.959        0.959 
## V7           1     58935.364    723649.721    730987.798    0.959        0.959 
## V8           1     58944.050    724443.690    731781.768    0.959        0.959 
## V14          1     58973.514    727143.135    734481.213    0.959        0.959 
## V13          1     58975.644    727338.628    734676.705    0.959        0.959 
## V9           1     58985.785    728270.264    735608.342    0.959        0.959 
## V15          1     58990.595    728712.542    736050.620    0.959        0.959 
## V16          1     59010.772    730570.885    737908.963    0.959        0.959 
## V5           1     59058.197    734957.211    742295.289    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V46 
## 
## 
##   Step 4 : AIC = 22115.63 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V23 + V24 + V25 + V27 + V28 + V29 + V30 + V31 + V33 + V34 + V35 + V36 + V37 + V38 + V39 + V41 + V42 + V43 + V44 + V45 + V47 + V48 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V41          1     22113.684         0.048      7338.153    1.000        1.000 
## V28          1     22113.687         0.051      7338.155    1.000        1.000 
## V31          1     22113.690         0.053      7338.158    1.000        1.000 
## V34          1     22113.696         0.059      7338.163    1.000        1.000 
## V38          1     22113.768         0.125      7338.229    1.000        1.000 
## V39          1     22113.770         0.127      7338.231    1.000        1.000 
## V23          1     22113.773         0.130      7338.235    1.000        1.000 
## V48          1     22113.793         0.147      7338.252    1.000        1.000 
## V25          1     22113.861         0.210      7338.315    1.000        1.000 
## V30          1     22113.869         0.217      7338.322    1.000        1.000 
## V43          1     22113.902         0.248      7338.353    1.000        1.000 
## V45          1     22113.958         0.299      7338.404    1.000        1.000 
## V29          1     22114.062         0.394      7338.499    1.000        1.000 
## V35          1     22114.094         0.424      7338.529    1.000        1.000 
## V21          1     22114.104         0.433      7338.537    1.000        1.000 
## V49          1     22114.183         0.505      7338.610    1.000        1.000 
## V22          1     22114.200         0.521      7338.626    1.000        1.000 
## V44          1     22114.315         0.626      7338.731    1.000        1.000 
## V47          1     22114.590         0.879      7338.984    1.000        1.000 
## V50          1     22114.602         0.890      7338.995    1.000        1.000 
## V36          1     22114.815         1.085      7339.190    1.000        1.000 
## V33          1     22115.282         1.513      7339.618    1.000        1.000 
## V42          1     22115.746         1.939      7340.044    1.000        1.000 
## V24          1     22115.819         2.006      7340.110    1.000        1.000 
## V27          1     22118.914         4.846      7342.950    1.000        1.000 
## V37          1     22119.597         5.472      7343.577    1.000        1.000 
## V1           1     28885.830      9767.288     17105.392    0.999        0.999 
## V2           1     36746.176     38343.306     45681.411    0.997        0.997 
## V52          1     45743.070    133276.403    140614.507    0.992        0.992 
## V51          1     48736.690    197072.585    204410.690    0.989        0.989 
## V17          1     58524.339    687223.911    694562.016    0.961        0.961 
## V11          1     58605.442    694299.357    701637.461    0.961        0.961 
## V4           1     58671.951    700155.355    707493.460    0.961        0.961 
## V18          1     58680.276    700891.771    708229.876    0.961        0.961 
## V12          1     58740.690    706258.988    713597.093    0.960        0.960 
## V10          1     58816.920    713089.545    720427.650    0.960        0.960 
## V6           1     58856.066    716622.454    723960.559    0.960        0.960 
## V19          1     58861.075    717075.782    724413.887    0.960        0.960 
## V20          1     58924.500    722840.401    730178.506    0.960        0.959 
## V3           1     58933.115    723626.978    730965.083    0.959        0.959 
## V7           1     58935.226    723819.837    731157.942    0.959        0.959 
## V8           1     58942.081    724446.418    731784.523    0.959        0.959 
## V14          1     58971.561    727147.371    734485.476    0.959        0.959 
## V13          1     58974.899    727453.875    734791.979    0.959        0.959 
## V9           1     58983.799    728271.543    735609.647    0.959        0.959 
## V15          1     58990.394    728878.012    736216.117    0.959        0.959 
## V16          1     59011.517    730824.015    738162.120    0.959        0.959 
## V5           1     59056.288    734965.638    742303.743    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V41 
## 
## 
##   Step 5 : AIC = 22113.68 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V23 + V24 + V25 + V27 + V28 + V29 + V30 + V31 + V33 + V34 + V35 + V36 + V37 + V38 + V39 + V42 + V43 + V44 + V45 + V47 + V48 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V28          1     22111.738         0.050      7338.202    1.000        1.000 
## V31          1     22111.744         0.055      7338.207    1.000        1.000 
## V34          1     22111.747         0.058      7338.210    1.000        1.000 
## V38          1     22111.820         0.125      7338.278    1.000        1.000 
## V39          1     22111.822         0.126      7338.279    1.000        1.000 
## V23          1     22111.825         0.129      7338.282    1.000        1.000 
## V48          1     22111.842         0.145      7338.298    1.000        1.000 
## V25          1     22111.916         0.213      7338.366    1.000        1.000 
## V30          1     22111.922         0.218      7338.371    1.000        1.000 
## V43          1     22111.956         0.249      7338.402    1.000        1.000 
## V45          1     22112.014         0.303      7338.455    1.000        1.000 
## V29          1     22112.118         0.398      7338.550    1.000        1.000 
## V35          1     22112.148         0.425      7338.578    1.000        1.000 
## V21          1     22112.152         0.429      7338.581    1.000        1.000 
## V49          1     22112.228         0.499      7338.652    1.000        1.000 
## V22          1     22112.248         0.517      7338.670    1.000        1.000 
## V44          1     22112.364         0.624      7338.776    1.000        1.000 
## V47          1     22112.641         0.878      7339.031    1.000        1.000 
## V50          1     22112.660         0.895      7339.047    1.000        1.000 
## V36          1     22112.864         1.082      7339.234    1.000        1.000 
## V33          1     22113.336         1.515      7339.668    1.000        1.000 
## V42          1     22113.795         1.936      7340.089    1.000        1.000 
## V24          1     22113.889         2.023      7340.175    1.000        1.000 
## V27          1     22116.963         4.843      7342.995    1.000        1.000 
## V37          1     22117.662         5.484      7343.637    1.000        1.000 
## V1           1     28883.831      9767.242     17105.395    0.999        0.999 
## V2           1     36744.987     38347.888     45686.041    0.997        0.997 
## V52          1     45741.202    133278.678    140616.830    0.992        0.992 
## V51          1     48734.710    197073.033    204411.186    0.989        0.989 
## V17          1     58522.423    687231.193    694569.346    0.961        0.961 
## V11          1     58604.649    694405.163    701743.316    0.961        0.961 
## V4           1     58670.038    700162.938    707501.091    0.961        0.961 
## V18          1     58679.769    701023.852    708362.005    0.961        0.960 
## V12          1     58738.754    706264.699    713602.851    0.960        0.960 
## V10          1     58815.460    713138.062    720476.215    0.960        0.960 
## V6           1     58854.066    716622.487    723960.640    0.960        0.960 
## V19          1     58859.974    717157.112    724495.265    0.960        0.960 
## V20          1     58923.121    722897.064    730235.217    0.960        0.959 
## V7           1     58935.601    724036.781    731374.933    0.959        0.959 
## V3           1     58935.653    724041.551    731379.703    0.959        0.959 
## V8           1     58940.676    724500.834    731838.986    0.959        0.959 
## V14          1     58970.158    727202.166    734540.319    0.959        0.959 
## V13          1     58974.715    727620.526    734958.679    0.959        0.959 
## V9           1     58981.811    728272.561    735610.714    0.959        0.959 
## V15          1     58988.877    728922.399    736260.552    0.959        0.959 
## V16          1     59013.085    731153.174    738491.326    0.959        0.959 
## V5           1     59054.412    734977.089    742315.241    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V28 
## 
## 
##   Step 6 : AIC = 22111.74 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V23 + V24 + V25 + V27 + V29 + V30 + V31 + V33 + V34 + V35 + V36 + V37 + V38 + V39 + V42 + V43 + V44 + V45 + V47 + V48 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V31          1     22109.797         0.054      7338.256    1.000        1.000 
## V34          1     22109.802         0.059      7338.261    1.000        1.000 
## V39          1     22109.872         0.123      7338.325    1.000        1.000 
## V23          1     22109.877         0.127      7338.329    1.000        1.000 
## V38          1     22109.877         0.127      7338.329    1.000        1.000 
## V48          1     22109.895         0.144      7338.346    1.000        1.000 
## V25          1     22109.973         0.215      7338.417    1.000        1.000 
## V30          1     22109.982         0.223      7338.425    1.000        1.000 
## V43          1     22110.008         0.247      7338.449    1.000        1.000 
## V45          1     22110.070         0.304      7338.507    1.000        1.000 
## V29          1     22110.178         0.403      7338.605    1.000        1.000 
## V35          1     22110.201         0.425      7338.627    1.000        1.000 
## V21          1     22110.204         0.427      7338.630    1.000        1.000 
## V49          1     22110.277         0.494      7338.697    1.000        1.000 
## V22          1     22110.306         0.520      7338.723    1.000        1.000 
## V44          1     22110.418         0.623      7338.826    1.000        1.000 
## V47          1     22110.700         0.882      7339.084    1.000        1.000 
## V50          1     22110.714         0.895      7339.097    1.000        1.000 
## V36          1     22110.923         1.087      7339.289    1.000        1.000 
## V33          1     22111.391         1.516      7339.718    1.000        1.000 
## V42          1     22111.841         1.928      7340.131    1.000        1.000 
## V24          1     22111.936         2.016      7340.218    1.000        1.000 
## V27          1     22115.012         4.838      7343.040    1.000        1.000 
## V37          1     22115.745         5.510      7343.713    1.000        1.000 
## V1           1     28881.856      9767.245     17105.448    0.999        0.999 
## V2           1     36743.949     38353.329     45691.532    0.997        0.997 
## V52          1     45739.208    133278.723    140616.926    0.992        0.992 
## V51          1     48732.887    197077.507    204415.709    0.989        0.989 
## V17          1     58521.237    687301.774    694639.976    0.961        0.961 
## V11          1     58602.827    694420.670    701758.872    0.961        0.961 
## V4           1     58671.129    700436.260    707774.463    0.961        0.961 
## V18          1     58678.020    701046.031    708384.233    0.961        0.961 
## V12          1     58739.551    706514.110    713852.313    0.960        0.960 
## V10          1     58813.491    713140.823    720479.026    0.960        0.960 
## V6           1     58852.175    716632.222    723970.425    0.960        0.960 
## V19          1     58859.363    717282.901    724621.104    0.960        0.960 
## V20          1     58921.121    722897.020    730235.222    0.960        0.959 
## V7           1     58933.705    724046.321    731384.524    0.959        0.959 
## V3           1     58934.170    724088.745    731426.947    0.959        0.959 
## V8           1     58938.703    724503.242    731841.445    0.959        0.959 
## V14          1     58970.060    727376.658    734714.861    0.959        0.959 
## V13          1     58972.931    727640.310    734978.513    0.959        0.959 
## V9           1     58979.890    728279.810    735618.013    0.959        0.959 
## V15          1     58989.483    729162.163    736500.366    0.959        0.959 
## V16          1     59012.053    731242.470    738580.673    0.959        0.959 
## V5           1     59052.414    734977.174    742315.377    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V31 
## 
## 
##   Step 7 : AIC = 22109.8 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V23 + V24 + V25 + V27 + V29 + V30 + V33 + V34 + V35 + V36 + V37 + V38 + V39 + V42 + V43 + V44 + V45 + V47 + V48 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V34          1     22107.861         0.059      7338.315    1.000        1.000 
## V38          1     22107.934         0.125      7338.381    1.000        1.000 
## V39          1     22107.934         0.125      7338.382    1.000        1.000 
## V23          1     22107.938         0.130      7338.386    1.000        1.000 
## V48          1     22107.956         0.146      7338.402    1.000        1.000 
## V25          1     22108.030         0.213      7338.469    1.000        1.000 
## V30          1     22108.038         0.221      7338.478    1.000        1.000 
## V43          1     22108.071         0.251      7338.507    1.000        1.000 
## V45          1     22108.125         0.301      7338.557    1.000        1.000 
## V29          1     22108.238         0.405      7338.661    1.000        1.000 
## V35          1     22108.254         0.420      7338.676    1.000        1.000 
## V21          1     22108.261         0.426      7338.682    1.000        1.000 
## V49          1     22108.337         0.495      7338.751    1.000        1.000 
## V22          1     22108.365         0.521      7338.777    1.000        1.000 
## V44          1     22108.476         0.623      7338.879    1.000        1.000 
## V47          1     22108.755         0.879      7339.135    1.000        1.000 
## V50          1     22108.776         0.898      7339.155    1.000        1.000 
## V36          1     22108.978         1.084      7339.340    1.000        1.000 
## V33          1     22109.454         1.520      7339.776    1.000        1.000 
## V42          1     22109.895         1.925      7340.181    1.000        1.000 
## V24          1     22110.000         2.021      7340.277    1.000        1.000 
## V27          1     22113.063         4.831      7343.087    1.000        1.000 
## V37          1     22113.792         5.500      7343.756    1.000        1.000 
## V1           1     28879.857      9767.195     17105.451    0.999        0.999 
## V2           1     36742.168     38354.532     45692.788    0.997        0.997 
## V52          1     45737.215    133278.798    140617.054    0.992        0.992 
## V51          1     48730.904    197077.895    204416.151    0.989        0.989 
## V17          1     58519.277    687305.170    694643.427    0.961        0.961 
## V11          1     58604.680    694758.622    702096.878    0.961        0.961 
## V4           1     58669.191    700441.731    707779.987    0.961        0.961 
## V18          1     58677.037    701136.006    708474.262    0.961        0.961 
## V12          1     58737.563    706515.158    713853.414    0.960        0.960 
## V10          1     58811.538    713145.037    720483.293    0.960        0.960 
## V6           1     58853.456    716929.134    724267.390    0.960        0.960 
## V19          1     58858.178    717356.598    724694.854    0.960        0.960 
## V20          1     58919.771    722956.302    730294.558    0.960        0.959 
## V7           1     58931.731    724048.614    731386.870    0.959        0.959 
## V3           1     58933.070    724171.009    731509.265    0.959        0.959 
## V8           1     58940.513    724851.691    732189.947    0.959        0.959 
## V14          1     58968.133    727383.347    734721.603    0.959        0.959 
## V13          1     58971.687    727709.756    735048.012    0.959        0.959 
## V9           1     58978.141    728302.860    735641.116    0.959        0.959 
## V15          1     58987.609    729173.716    736511.972    0.959        0.959 
## V16          1     59011.301    731357.629    738695.885    0.959        0.959 
## V5           1     59053.413    735255.364    742593.620    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V34 
## 
## 
##   Step 8 : AIC = 22107.86 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V23 + V24 + V25 + V27 + V29 + V30 + V33 + V35 + V36 + V37 + V38 + V39 + V42 + V43 + V44 + V45 + V47 + V48 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V38          1     22105.995         0.123      7338.438    1.000        1.000 
## V23          1     22105.997         0.125      7338.440    1.000        1.000 
## V39          1     22105.997         0.125      7338.440    1.000        1.000 
## V48          1     22106.023         0.149      7338.464    1.000        1.000 
## V25          1     22106.095         0.214      7338.529    1.000        1.000 
## V30          1     22106.106         0.225      7338.540    1.000        1.000 
## V43          1     22106.134         0.250      7338.565    1.000        1.000 
## V45          1     22106.188         0.300      7338.615    1.000        1.000 
## V29          1     22106.306         0.409      7338.723    1.000        1.000 
## V35          1     22106.317         0.418      7338.733    1.000        1.000 
## V21          1     22106.317         0.418      7338.733    1.000        1.000 
## V49          1     22106.396         0.491      7338.806    1.000        1.000 
## V22          1     22106.429         0.521      7338.836    1.000        1.000 
## V44          1     22106.551         0.633      7338.948    1.000        1.000 
## V47          1     22106.831         0.890      7339.205    1.000        1.000 
## V50          1     22106.844         0.901      7339.216    1.000        1.000 
## V36          1     22107.043         1.084      7339.399    1.000        1.000 
## V33          1     22107.523         1.524      7339.839    1.000        1.000 
## V42          1     22107.956         1.922      7340.236    1.000        1.000 
## V24          1     22108.062         2.018      7340.333    1.000        1.000 
## V27          1     22111.140         4.843      7343.158    1.000        1.000 
## V37          1     22111.862         5.505      7343.820    1.000        1.000 
## V1           1     28878.494      9768.498     17106.813    0.999        0.999 
## V2           1     36740.212     38354.720     45693.035    0.997        0.997 
## V52          1     45735.516    133284.025    140622.340    0.992        0.992 
## V51          1     48729.545    197094.213    204432.528    0.989        0.989 
## V17          1     58519.236    687475.239    694813.554    0.961        0.961 
## V11          1     58603.781    694855.117    702193.432    0.961        0.961 
## V4           1     58669.816    700673.844    708012.159    0.961        0.961 
## V18          1     58675.057    701137.691    708476.006    0.961        0.961 
## V12          1     58735.563    706515.099    713853.414    0.960        0.960 
## V10          1     58810.422    713224.530    720562.845    0.960        0.960 
## V6           1     58852.601    717032.690    724371.004    0.960        0.960 
## V19          1     58856.472    717383.221    724721.536    0.960        0.960 
## V20          1     58922.046    723346.443    730684.758    0.959        0.959 
## V7           1     58929.736    724048.962    731387.277    0.959        0.959 
## V3           1     58931.144    724177.735    731516.050    0.959        0.959 
## V8           1     58938.517    724852.066    732190.381    0.959        0.959 
## V14          1     58966.184    727388.000    734726.315    0.959        0.959 
## V13          1     58971.357    727863.062    735201.376    0.959        0.959 
## V9           1     58976.322    728319.437    735657.752    0.959        0.959 
## V15          1     58985.694    729181.544    736519.859    0.959        0.959 
## V16          1     59011.002    731514.590    738852.905    0.959        0.959 
## V5           1     59051.867    735297.464    742635.779    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V38 
## 
## 
##   Step 9 : AIC = 22105.99 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V23 + V24 + V25 + V27 + V29 + V30 + V33 + V35 + V36 + V37 + V39 + V42 + V43 + V44 + V45 + V47 + V48 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V39          1     22104.134         0.128      7338.565    1.000        1.000 
## V23          1     22104.137         0.131      7338.568    1.000        1.000 
## V48          1     22104.155         0.147      7338.585    1.000        1.000 
## V25          1     22104.226         0.212      7338.650    1.000        1.000 
## V30          1     22104.242         0.226      7338.664    1.000        1.000 
## V43          1     22104.272         0.254      7338.692    1.000        1.000 
## V45          1     22104.319         0.297      7338.735    1.000        1.000 
## V29          1     22104.441         0.409      7338.847    1.000        1.000 
## V35          1     22104.450         0.417      7338.855    1.000        1.000 
## V21          1     22104.453         0.420      7338.858    1.000        1.000 
## V49          1     22104.525         0.487      7338.924    1.000        1.000 
## V22          1     22104.559         0.517      7338.955    1.000        1.000 
## V44          1     22104.702         0.649      7339.086    1.000        1.000 
## V47          1     22104.959         0.884      7339.322    1.000        1.000 
## V50          1     22104.972         0.896      7339.334    1.000        1.000 
## V36          1     22105.162         1.071      7339.508    1.000        1.000 
## V33          1     22105.643         1.512      7339.950    1.000        1.000 
## V42          1     22106.089         1.921      7340.358    1.000        1.000 
## V24          1     22106.206         2.028      7340.466    1.000        1.000 
## V27          1     22109.267         4.836      7343.274    1.000        1.000 
## V37          1     22109.995         5.504      7343.942    1.000        1.000 
## V1           1     28878.585      9772.845     17111.282    0.999        0.999 
## V2           1     36738.957     38358.851     45697.289    0.997        0.997 
## V52          1     45736.011    133327.755    140666.193    0.992        0.992 
## V51          1     48730.139    197160.358    204498.796    0.989        0.989 
## V17          1     58519.695    687688.594    695027.032    0.961        0.961 
## V11          1     58601.898    694865.339    702203.777    0.961        0.961 
## V4           1     58669.863    700854.842    708193.279    0.961        0.961 
## V18          1     58673.233    701153.217    708491.654    0.961        0.961 
## V12          1     58737.099    706830.488    714168.926    0.960        0.960 
## V10          1     58808.509    713232.263    720570.701    0.960        0.960 
## V6           1     58850.756    717046.577    724385.015    0.960        0.960 
## V19          1     58856.072    717528.006    724866.444    0.960        0.960 
## V20          1     58920.529    723390.442    730728.880    0.959        0.959 
## V7           1     58928.249    724095.795    731434.233    0.959        0.959 
## V3           1     58929.900    724246.727    731585.165    0.959        0.959 
## V8           1     58936.601    724859.579    732198.016    0.959        0.959 
## V14          1     58971.242    728036.192    735374.630    0.959        0.959 
## V13          1     58973.238    728219.669    735558.106    0.959        0.959 
## V9           1     58976.248    728496.379    735834.816    0.959        0.959 
## V15          1     58984.109    729219.616    736558.054    0.959        0.959 
## V16          1     59009.048    731518.742    738857.180    0.959        0.959 
## V5           1     59050.202    735328.463    742666.900    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V39 
## 
## 
##   Step 10 : AIC = 22104.13 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V23 + V24 + V25 + V27 + V29 + V30 + V33 + V35 + V36 + V37 + V42 + V43 + V44 + V45 + V47 + V48 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V23          1     22102.278         0.132      7338.697    1.000        1.000 
## V48          1     22102.300         0.152      7338.717    1.000        1.000 
## V25          1     22102.364         0.211      7338.776    1.000        1.000 
## V30          1     22102.383         0.228      7338.794    1.000        1.000 
## V43          1     22102.409         0.252      7338.818    1.000        1.000 
## V45          1     22102.465         0.303      7338.869    1.000        1.000 
## V29          1     22102.572         0.402      7338.967    1.000        1.000 
## V21          1     22102.588         0.416      7338.981    1.000        1.000 
## V35          1     22102.588         0.416      7338.982    1.000        1.000 
## V49          1     22102.660         0.482      7339.048    1.000        1.000 
## V22          1     22102.712         0.530      7339.095    1.000        1.000 
## V44          1     22102.839         0.647      7339.212    1.000        1.000 
## V47          1     22103.107         0.892      7339.458    1.000        1.000 
## V50          1     22103.117         0.901      7339.467    1.000        1.000 
## V36          1     22103.291         1.061      7339.627    1.000        1.000 
## V33          1     22103.798         1.526      7340.092    1.000        1.000 
## V42          1     22104.237         1.929      7340.494    1.000        1.000 
## V24          1     22104.345         2.028      7340.593    1.000        1.000 
## V27          1     22107.391         4.823      7343.388    1.000        1.000 
## V37          1     22108.120         5.491      7344.057    1.000        1.000 
## V1           1     28877.549      9774.778     17113.344    0.999        0.999 
## V2           1     36741.629     38385.414     45723.979    0.997        0.997 
## V52          1     45736.556    133372.377    140710.942    0.992        0.992 
## V51          1     48730.431    197218.832    204557.398    0.989        0.989 
## V17          1     58518.152    687728.230    695066.796    0.961        0.961 
## V11          1     58599.970    694871.517    702210.083    0.961        0.961 
## V4           1     58669.294    700981.414    708319.980    0.961        0.961 
## V18          1     58671.417    701169.392    708507.957    0.961        0.961 
## V12          1     58741.123    707368.141    714706.707    0.960        0.960 
## V10          1     58806.512    713232.362    720570.927    0.960        0.960 
## V6           1     58848.767    717047.434    724386.000    0.960        0.960 
## V19          1     58854.095    717529.948    724868.513    0.960        0.960 
## V7           1     58926.328    724102.889    731441.454    0.959        0.959 
## V3           1     58928.917    724339.555    731678.120    0.959        0.959 
## V20          1     58934.942    724890.666    732229.232    0.959        0.959 
## V8           1     58936.792    725059.956    732398.521    0.959        0.959 
## V14          1     58969.904    728096.897    735435.463    0.959        0.959 
## V13          1     58971.257    728221.215    735559.780    0.959        0.959 
## V9           1     58975.463    728607.984    735946.549    0.959        0.959 
## V15          1     58982.512    729256.527    736595.092    0.959        0.959 
## V16          1     59007.052    731518.995    738857.560    0.959        0.959 
## V5           1     59048.504    735356.330    742694.896    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V23 
## 
## 
##   Step 11 : AIC = 22102.28 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V24 + V25 + V27 + V29 + V30 + V33 + V35 + V36 + V37 + V42 + V43 + V44 + V45 + V47 + V48 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V48          1     22100.451         0.159      7338.856    1.000        1.000 
## V25          1     22100.511         0.214      7338.911    1.000        1.000 
## V30          1     22100.520         0.222      7338.919    1.000        1.000 
## V43          1     22100.553         0.253      7338.950    1.000        1.000 
## V45          1     22100.615         0.309      7339.006    1.000        1.000 
## V29          1     22100.719         0.404      7339.101    1.000        1.000 
## V21          1     22100.725         0.410      7339.107    1.000        1.000 
## V35          1     22100.737         0.421      7339.118    1.000        1.000 
## V49          1     22100.806         0.485      7339.182    1.000        1.000 
## V22          1     22100.867         0.540      7339.238    1.000        1.000 
## V44          1     22100.982         0.646      7339.343    1.000        1.000 
## V47          1     22101.241         0.884      7339.581    1.000        1.000 
## V50          1     22101.248         0.889      7339.587    1.000        1.000 
## V36          1     22101.429         1.056      7339.753    1.000        1.000 
## V33          1     22101.936         1.521      7340.218    1.000        1.000 
## V42          1     22102.384         1.932      7340.629    1.000        1.000 
## V24          1     22102.471         2.012      7340.709    1.000        1.000 
## V27          1     22105.537         4.825      7343.522    1.000        1.000 
## V37          1     22106.290         5.516      7344.213    1.000        1.000 
## V1           1     28876.548      9776.785     17115.482    0.999        0.999 
## V2           1     36739.753     38385.992     45724.690    0.997        0.997 
## V52          1     45735.416    133387.361    140726.058    0.992        0.992 
## V51          1     48730.559    197273.108    204611.805    0.989        0.989 
## V17          1     58517.096    687810.043    695148.740    0.961        0.961 
## V11          1     58598.263    694897.035    702235.732    0.961        0.961 
## V4           1     58667.615    701009.669    708348.367    0.961        0.961 
## V18          1     58671.392    701344.147    708682.845    0.961        0.961 
## V12          1     58740.574    707497.688    714836.385    0.960        0.960 
## V10          1     58806.133    713378.219    720716.917    0.960        0.960 
## V6           1     58851.302    717458.003    724796.701    0.960        0.960 
## V19          1     58852.529    717569.158    724907.856    0.960        0.960 
## V7           1     58924.424    724111.478    731450.175    0.959        0.959 
## V3           1     58927.678    724408.968    731747.665    0.959        0.959 
## V20          1     58932.983    724894.302    732233.000    0.959        0.959 
## V8           1     58935.064    725084.716    732423.413    0.959        0.959 
## V14          1     58968.136    728118.113    735456.810    0.959        0.959 
## V13          1     58969.261    728221.449    735560.146    0.959        0.959 
## V9           1     58976.043    728845.181    736183.878    0.959        0.959 
## V15          1     58981.334    729332.140    736670.837    0.959        0.959 
## V16          1     59005.271    731539.025    738877.722    0.959        0.959 
## V5           1     59046.658    735370.460    742709.157    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V48 
## 
## 
##   Step 12 : AIC = 22100.45 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V24 + V25 + V27 + V29 + V30 + V33 + V35 + V36 + V37 + V42 + V43 + V44 + V45 + V47 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V25          1     22098.677         0.208      7339.064    1.000        1.000 
## V30          1     22098.697         0.226      7339.082    1.000        1.000 
## V43          1     22098.726         0.252      7339.108    1.000        1.000 
## V45          1     22098.779         0.301      7339.157    1.000        1.000 
## V29          1     22098.881         0.395      7339.251    1.000        1.000 
## V21          1     22098.904         0.416      7339.272    1.000        1.000 
## V35          1     22098.905         0.416      7339.272    1.000        1.000 
## V49          1     22098.991         0.495      7339.351    1.000        1.000 
## V22          1     22099.036         0.537      7339.393    1.000        1.000 
## V44          1     22099.164         0.654      7339.510    1.000        1.000 
## V50          1     22099.414         0.883      7339.739    1.000        1.000 
## V47          1     22099.432         0.900      7339.756    1.000        1.000 
## V36          1     22099.592         1.047      7339.903    1.000        1.000 
## V33          1     22100.098         1.510      7340.366    1.000        1.000 
## V42          1     22100.561         1.936      7340.792    1.000        1.000 
## V24          1     22100.652         2.019      7340.875    1.000        1.000 
## V27          1     22103.719         4.833      7343.689    1.000        1.000 
## V37          1     22104.420         5.476      7344.332    1.000        1.000 
## V1           1     28874.557      9776.644     17115.500    0.999        0.999 
## V2           1     36737.763     38385.886     45724.742    0.997        0.997 
## V52          1     45734.209    133401.159    140740.015    0.992        0.992 
## V51          1     48728.651    197275.294    204614.150    0.989        0.989 
## V17          1     58515.860    687876.234    695215.091    0.961        0.961 
## V11          1     58596.514    694918.980    702257.836    0.961        0.961 
## V4           1     58667.034    701135.114    708473.970    0.961        0.961 
## V18          1     58670.507    701442.684    708781.540    0.961        0.961 
## V12          1     58738.674    707506.404    714845.260    0.960        0.960 
## V10          1     58804.157    713380.277    720719.133    0.960        0.960 
## V6           1     58849.785    717501.583    724840.439    0.960        0.960 
## V19          1     58852.180    717718.590    725057.446    0.960        0.960 
## V7           1     58923.269    724188.583    731527.439    0.959        0.959 
## V3           1     58925.971    724435.648    731774.504    0.959        0.959 
## V20          1     58932.908    725070.278    732409.134    0.959        0.959 
## V8           1     58933.771    725149.288    732488.144    0.959        0.959 
## V13          1     58967.307    728225.559    735564.415    0.959        0.959 
## V14          1     58967.469    728240.415    735579.271    0.959        0.959 
## V9           1     58975.624    728990.439    736329.295    0.959        0.959 
## V15          1     58979.756    729370.792    736709.648    0.959        0.959 
## V16          1     59004.961    731694.986    739033.843    0.959        0.959 
## V5           1     59046.579    735548.660    742887.516    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V25 
## 
## 
##   Step 13 : AIC = 22098.68 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V24 + V27 + V29 + V30 + V33 + V35 + V36 + V37 + V42 + V43 + V44 + V45 + V47 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V30          1     22096.922         0.224      7339.288    1.000        1.000 
## V43          1     22096.954         0.254      7339.317    1.000        1.000 
## V45          1     22097.015         0.309      7339.373    1.000        1.000 
## V29          1     22097.108         0.395      7339.458    1.000        1.000 
## V35          1     22097.120         0.406      7339.470    1.000        1.000 
## V21          1     22097.138         0.423      7339.486    1.000        1.000 
## V49          1     22097.205         0.484      7339.548    1.000        1.000 
## V22          1     22097.252         0.527      7339.591    1.000        1.000 
## V44          1     22097.388         0.652      7339.716    1.000        1.000 
## V50          1     22097.628         0.872      7339.935    1.000        1.000 
## V47          1     22097.653         0.895      7339.958    1.000        1.000 
## V36          1     22097.806         1.035      7340.099    1.000        1.000 
## V33          1     22098.314         1.501      7340.565    1.000        1.000 
## V42          1     22098.799         1.947      7341.010    1.000        1.000 
## V24          1     22098.890         2.029      7341.093    1.000        1.000 
## V27          1     22101.954         4.841      7343.904    1.000        1.000 
## V37          1     22102.635         5.466      7344.530    1.000        1.000 
## V1           1     28872.566      9776.455     17115.519    0.999        0.999 
## V2           1     36736.137     38387.820     45726.884    0.997        0.997 
## V52          1     45732.344    133403.328    140742.391    0.992        0.992 
## V51          1     48726.675    197275.693    204614.756    0.989        0.989 
## V17          1     58514.155    687901.697    695240.761    0.961        0.961 
## V11          1     58595.669    695020.126    702359.189    0.961        0.961 
## V4           1     58665.067    701137.833    708476.897    0.961        0.961 
## V18          1     58670.168    701589.602    708928.666    0.961        0.961 
## V12          1     58737.803    707607.076    714946.140    0.960        0.960 
## V10          1     58809.226    714016.990    721356.054    0.960        0.960 
## V6           1     58849.078    717618.456    724957.520    0.960        0.960 
## V19          1     58850.319    717730.922    725069.986    0.960        0.960 
## V7           1     58922.812    724329.435    731668.498    0.959        0.959 
## V3           1     58925.386    724564.879    731903.943    0.959        0.959 
## V8           1     58932.071    725176.590    732515.653    0.959        0.959 
## V20          1     58932.875    725250.170    732589.234    0.959        0.959 
## V14          1     58965.597    728251.965    735591.028    0.959        0.959 
## V13          1     58965.761    728267.065    735606.128    0.959        0.959 
## V9           1     58974.379    729059.778    736398.842    0.959        0.959 
## V15          1     58977.760    729370.908    736709.972    0.959        0.959 
## V16          1     59005.143    731896.299    739235.363    0.959        0.959 
## V5           1     59045.015    735588.921    742927.985    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V30 
## 
## 
##   Step 14 : AIC = 22096.92 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V24 + V27 + V29 + V33 + V35 + V36 + V37 + V42 + V43 + V44 + V45 + V47 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V43          1     22095.186         0.242      7339.530    1.000        1.000 
## V45          1     22095.265         0.314      7339.602    1.000        1.000 
## V29          1     22095.355         0.397      7339.685    1.000        1.000 
## V35          1     22095.357         0.399      7339.687    1.000        1.000 
## V21          1     22095.387         0.426      7339.714    1.000        1.000 
## V49          1     22095.443         0.477      7339.766    1.000        1.000 
## V22          1     22095.511         0.540      7339.829    1.000        1.000 
## V44          1     22095.635         0.654      7339.942    1.000        1.000 
## V50          1     22095.854         0.855      7340.143    1.000        1.000 
## V47          1     22095.889         0.887      7340.175    1.000        1.000 
## V36          1     22096.037         1.023      7340.311    1.000        1.000 
## V33          1     22096.553         1.496      7340.784    1.000        1.000 
## V42          1     22097.033         1.937      7341.225    1.000        1.000 
## V24          1     22097.177         2.069      7341.357    1.000        1.000 
## V27          1     22100.199         4.842      7344.130    1.000        1.000 
## V37          1     22100.886         5.472      7344.761    1.000        1.000 
## V1           1     28870.568      9776.236     17115.524    0.999        0.999 
## V2           1     36734.138     38387.601     45726.890    0.997        0.997 
## V52          1     45730.359    133403.360    140742.648    0.992        0.992 
## V51          1     48725.058    197285.261    204624.550    0.989        0.989 
## V17          1     58512.755    687953.570    695292.858    0.961        0.961 
## V11          1     58593.671    695020.015    702359.304    0.961        0.961 
## V4           1     58664.202    701238.175    708577.463    0.961        0.961 
## V18          1     58668.294    701600.568    708939.856    0.961        0.961 
## V12          1     58735.926    707617.853    714957.141    0.960        0.960 
## V10          1     58809.414    714214.054    721553.342    0.960        0.960 
## V6           1     58847.090    717619.375    724958.664    0.960        0.960 
## V19          1     58849.394    717828.161    725167.449    0.960        0.960 
## V7           1     58920.910    724338.222    731677.510    0.959        0.959 
## V3           1     58924.272    724645.623    731984.911    0.959        0.959 
## V20          1     58930.888    725251.109    732590.398    0.959        0.959 
## V8           1     58934.814    725610.659    732949.948    0.959        0.959 
## V14          1     58963.748    728265.624    735604.912    0.959        0.959 
## V13          1     58965.317    728409.913    735749.201    0.959        0.959 
## V9           1     58975.261    729324.769    736664.057    0.959        0.959 
## V15          1     58975.914    729384.914    736724.202    0.959        0.959 
## V16          1     59003.467    731925.995    739265.283    0.959        0.959 
## V5           1     59043.331    735618.080    742957.368    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V43 
## 
## 
##   Step 15 : AIC = 22095.19 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V24 + V27 + V29 + V33 + V35 + V36 + V37 + V42 + V44 + V45 + V47 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V45          1     22093.526         0.312      7339.842    1.000        1.000 
## V35          1     22093.604         0.383      7339.914    1.000        1.000 
## V29          1     22093.621         0.398      7339.929    1.000        1.000 
## V21          1     22093.650         0.425      7339.955    1.000        1.000 
## V49          1     22093.708         0.478      7340.009    1.000        1.000 
## V22          1     22093.777         0.542      7340.072    1.000        1.000 
## V44          1     22093.899         0.654      7340.184    1.000        1.000 
## V50          1     22094.108         0.846      7340.376    1.000        1.000 
## V47          1     22094.164         0.897      7340.427    1.000        1.000 
## V36          1     22094.279         1.002      7340.533    1.000        1.000 
## V33          1     22094.818         1.497      7341.027    1.000        1.000 
## V42          1     22095.295         1.934      7341.464    1.000        1.000 
## V24          1     22095.394         2.026      7341.556    1.000        1.000 
## V27          1     22098.430         4.812      7344.342    1.000        1.000 
## V37          1     22099.139         5.462      7344.992    1.000        1.000 
## V1           1     28868.689      9776.253     17115.783    0.999        0.999 
## V2           1     36733.582     38395.612     45735.142    0.997        0.997 
## V52          1     45728.359    133403.121    140742.651    0.992        0.992 
## V51          1     48723.203    197288.736    204628.267    0.989        0.989 
## V17          1     58511.167    687989.145    695328.676    0.961        0.961 
## V11          1     58591.694    695021.822    702361.352    0.961        0.961 
## V4           1     58662.533    701267.211    708606.741    0.961        0.961 
## V18          1     58666.329    701603.415    708942.945    0.961        0.961 
## V12          1     58734.026    707626.563    714966.094    0.960        0.960 
## V10          1     58811.037    714540.533    721880.064    0.960        0.960 
## V6           1     58845.616    717666.751    725006.281    0.960        0.960 
## V19          1     58847.963    717879.431    725218.962    0.960        0.960 
## V7           1     58919.057    724351.398    731690.929    0.959        0.959 
## V3           1     58922.279    724646.058    731985.588    0.959        0.959 
## V20          1     58929.479    725305.008    732644.539    0.959        0.959 
## V8           1     58933.332    725657.799    732997.329    0.959        0.959 
## V14          1     58961.912    728280.477    735620.007    0.959        0.959 
## V13          1     58964.021    728474.381    735813.911    0.959        0.959 
## V9           1     58975.203    729503.364    736842.895    0.959        0.959 
## V15          1     58975.836    729561.677    736901.208    0.959        0.959 
## V16          1     59002.543    732025.170    739364.701    0.959        0.959 
## V5           1     59044.715    735932.037    743271.567    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V45 
## 
## 
##   Step 16 : AIC = 22093.53 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V24 + V27 + V29 + V33 + V35 + V36 + V37 + V42 + V44 + V47 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V35          1     22091.932         0.372      7340.214    1.000        1.000 
## V29          1     22091.971         0.408      7340.250    1.000        1.000 
## V21          1     22091.998         0.433      7340.275    1.000        1.000 
## V49          1     22092.046         0.477      7340.319    1.000        1.000 
## V22          1     22092.108         0.534      7340.376    1.000        1.000 
## V44          1     22092.270         0.682      7340.525    1.000        1.000 
## V50          1     22092.437         0.835      7340.678    1.000        1.000 
## V47          1     22092.519         0.911      7340.753    1.000        1.000 
## V36          1     22092.621         1.004      7340.847    1.000        1.000 
## V33          1     22093.140         1.480      7341.322    1.000        1.000 
## V42          1     22093.639         1.938      7341.780    1.000        1.000 
## V24          1     22093.735         2.026      7341.868    1.000        1.000 
## V27          1     22096.746         4.789      7344.632    1.000        1.000 
## V37          1     22097.424         5.411      7345.254    1.000        1.000 
## V1           1     28867.279      9777.203     17117.046    0.999        0.999 
## V2           1     36731.639     38395.624     45735.466    0.997        0.997 
## V52          1     45726.619    133407.385    140747.228    0.992        0.992 
## V51          1     48721.668    197300.298    204640.140    0.989        0.989 
## V17          1     58509.175    687989.575    695329.418    0.961        0.961 
## V11          1     58597.186    695679.467    703019.309    0.961        0.961 
## V4           1     58660.540    701267.525    708607.367    0.961        0.961 
## V18          1     58664.540    701621.796    708961.639    0.961        0.961 
## V12          1     58732.093    707632.259    714972.102    0.960        0.960 
## V10          1     58809.043    714540.758    721880.600    0.960        0.960 
## V19          1     58847.520    718020.229    725360.072    0.960        0.960 
## V6           1     58848.736    718130.541    725470.383    0.960        0.960 
## V7           1     58917.267    724370.307    731710.150    0.959        0.959 
## V3           1     58920.295    724647.204    731987.047    0.959        0.959 
## V20          1     58929.483    725488.178    732828.021    0.959        0.959 
## V8           1     58931.616    725683.543    733023.385    0.959        0.959 
## V14          1     58959.976    728286.052    735625.894    0.959        0.959 
## V13          1     58962.598    728527.138    735866.981    0.959        0.959 
## V9           1     58973.276    729509.717    736849.560    0.959        0.959 
## V15          1     58973.975    729574.083    736913.926    0.959        0.959 
## V16          1     59000.554    732025.935    739365.777    0.959        0.959 
## V5           1     59042.846    735943.886    743283.729    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V35 
## 
## 
##   Step 17 : AIC = 22091.93 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V24 + V27 + V29 + V33 + V36 + V37 + V42 + V44 + V47 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V29          1     22090.383         0.413      7340.628    1.000        1.000 
## V21          1     22090.402         0.431      7340.645    1.000        1.000 
## V49          1     22090.454         0.479      7340.693    1.000        1.000 
## V22          1     22090.507         0.527      7340.742    1.000        1.000 
## V44          1     22090.689         0.695      7340.909    1.000        1.000 
## V50          1     22090.833         0.826      7341.041    1.000        1.000 
## V47          1     22090.922         0.908      7341.123    1.000        1.000 
## V36          1     22091.045         1.021      7341.235    1.000        1.000 
## V33          1     22091.533         1.469      7341.684    1.000        1.000 
## V42          1     22092.040         1.934      7342.148    1.000        1.000 
## V24          1     22092.151         2.035      7342.250    1.000        1.000 
## V27          1     22095.145         4.783      7344.997    1.000        1.000 
## V37          1     22095.826         5.409      7345.623    1.000        1.000 
## V1           1     28865.472      9777.243     17117.458    0.999        0.999 
## V2           1     36729.989     38397.253     45737.467    0.997        0.997 
## V52          1     45724.716    133408.722    140748.937    0.992        0.992 
## V51          1     48721.046    197335.182    204675.397    0.989        0.989 
## V17          1     58507.344    688003.851    695344.066    0.961        0.961 
## V11          1     58595.574    695713.130    703053.344    0.961        0.961 
## V4           1     58660.131    701408.002    708748.217    0.961        0.961 
## V18          1     58662.881    701651.653    708991.867    0.961        0.961 
## V12          1     58730.625    707679.409    715019.624    0.960        0.960 
## V10          1     58807.128    714548.110    721888.324    0.960        0.960 
## V6           1     58848.124    718255.990    725596.204    0.960        0.960 
## V19          1     58848.142    718257.633    725597.847    0.960        0.960 
## V7           1     58915.594    724399.817    731740.031    0.959        0.959 
## V3           1     58919.320    724740.621    732080.835    0.959        0.959 
## V20          1     58928.594    725589.559    732929.773    0.959        0.959 
## V8           1     58929.817    725701.596    733041.811    0.959        0.959 
## V14          1     58957.978    728285.882    735626.096    0.959        0.959 
## V13          1     58960.678    728534.110    735874.324    0.959        0.959 
## V9           1     58971.503    729530.285    736870.499    0.959        0.959 
## V15          1     58972.371    729610.228    736950.442    0.959        0.959 
## V16          1     58999.484    732111.414    739451.628    0.959        0.959 
## V5           1     59041.735    736026.080    743366.294    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V29 
## 
## 
##   Step 18 : AIC = 22090.38 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V21 + V22 + V24 + V27 + V33 + V36 + V37 + V42 + V44 + V47 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V21          1     22088.876         0.452      7341.080    1.000        1.000 
## V49          1     22088.912         0.486      7341.113    1.000        1.000 
## V22          1     22088.939         0.510      7341.138    1.000        1.000 
## V44          1     22089.125         0.681      7341.309    1.000        1.000 
## V50          1     22089.288         0.830      7341.458    1.000        1.000 
## V47          1     22089.378         0.913      7341.541    1.000        1.000 
## V36          1     22089.510         1.034      7341.662    1.000        1.000 
## V33          1     22090.002         1.485      7342.113    1.000        1.000 
## V42          1     22090.508         1.950      7342.578    1.000        1.000 
## V24          1     22090.590         2.025      7342.653    1.000        1.000 
## V27          1     22093.587         4.776      7345.404    1.000        1.000 
## V37          1     22094.278         5.410      7346.038    1.000        1.000 
## V1           1     28863.586      9777.074     17117.702    0.999        0.999 
## V2           1     36728.231     38398.219     45738.847    0.997        0.997 
## V52          1     45724.035    133431.502    140772.130    0.992        0.992 
## V51          1     48719.374    197343.169    204683.797    0.989        0.989 
## V17          1     58505.555    688021.782    695362.410    0.961        0.961 
## V11          1     58593.922    695743.320    703083.948    0.961        0.961 
## V4           1     58658.832    701469.738    708810.366    0.961        0.961 
## V18          1     58660.899    701652.820    708993.448    0.961        0.961 
## V12          1     58728.913    707704.725    715045.352    0.960        0.960 
## V10          1     58806.442    714666.197    722006.825    0.960        0.960 
## V19          1     58846.152    718258.129    725598.757    0.960        0.960 
## V6           1     58846.190    718261.520    725602.148    0.960        0.960 
## V7           1     58916.128    724631.125    731971.753    0.959        0.959 
## V3           1     58917.336    724741.690    732082.318    0.959        0.959 
## V20          1     58926.601    725589.781    732930.409    0.959        0.959 
## V8           1     58927.931    725711.625    733052.253    0.959        0.959 
## V14          1     58957.234    728400.955    735741.583    0.959        0.959 
## V13          1     58959.607    728619.130    735959.757    0.959        0.959 
## V9           1     58969.513    729530.774    736871.401    0.959        0.959 
## V15          1     58970.914    729659.810    737000.438    0.959        0.959 
## V16          1     58998.274    732184.001    739524.629    0.959        0.959 
## V5           1     59039.841    736035.519    743376.147    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V21 
## 
## 
##   Step 19 : AIC = 22088.88 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V22 + V24 + V27 + V33 + V36 + V37 + V42 + V44 + V47 + V49 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V49          1     22087.397         0.478      7341.558    1.000        1.000 
## V22          1     22087.430         0.509      7341.589    1.000        1.000 
## V44          1     22087.606         0.670      7341.750    1.000        1.000 
## V50          1     22087.806         0.853      7341.933    1.000        1.000 
## V47          1     22087.867         0.910      7341.990    1.000        1.000 
## V36          1     22087.996         1.028      7342.108    1.000        1.000 
## V33          1     22088.499         1.489      7342.569    1.000        1.000 
## V42          1     22088.991         1.941      7343.021    1.000        1.000 
## V24          1     22089.079         2.022      7343.102    1.000        1.000 
## V27          1     22092.079         4.775      7345.855    1.000        1.000 
## V37          1     22092.747         5.388      7346.469    1.000        1.000 
## V1           1     28861.779      9777.034     17118.114    0.999        0.999 
## V2           1     36726.304     38398.189     45739.270    0.997        0.997 
## V52          1     45722.037    133431.086    140772.166    0.992        0.992 
## V51          1     48717.375    197342.728    204683.808    0.989        0.989 
## V17          1     58503.773    688040.266    695381.346    0.961        0.961 
## V11          1     58594.004    695925.808    703266.888    0.961        0.961 
## V18          1     58659.197    701678.804    709019.884    0.961        0.961 
## V4           1     58659.290    701687.000    709028.081    0.961        0.961 
## V12          1     58728.377    707835.121    715176.201    0.960        0.960 
## V10          1     58804.792    714697.330    722038.410    0.960        0.960 
## V6           1     58844.221    718263.904    725604.985    0.960        0.960 
## V19          1     58845.181    718350.958    725692.038    0.960        0.960 
## V3           1     58915.451    724751.701    732092.781    0.959        0.959 
## V7           1     58915.659    724770.723    732111.803    0.959        0.959 
## V20          1     58924.919    725618.445    732959.526    0.959        0.959 
## V8           1     58926.056    725722.625    733063.705    0.959        0.959 
## V14          1     58955.296    728406.227    735747.308    0.959        0.959 
## V13          1     58966.008    729391.773    736732.853    0.959        0.959 
## V9           1     58967.810    729557.728    736898.808    0.959        0.959 
## V15          1     58969.173    729683.199    737024.279    0.959        0.959 
## V16          1     58996.500    732204.459    739545.540    0.959        0.959 
## V5           1     59040.966    736325.451    743666.531    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V49 
## 
## 
##   Step 20 : AIC = 22087.4 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V22 + V24 + V27 + V33 + V36 + V37 + V42 + V44 + V47 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V22          1     22085.964         0.520      7342.078    1.000        1.000 
## V44          1     22086.131         0.674      7342.232    1.000        1.000 
## V50          1     22086.324         0.850      7342.409    1.000        1.000 
## V47          1     22086.395         0.915      7342.474    1.000        1.000 
## V36          1     22086.535         1.044      7342.603    1.000        1.000 
## V33          1     22086.999         1.469      7343.028    1.000        1.000 
## V42          1     22087.519         1.947      7343.506    1.000        1.000 
## V24          1     22087.644         2.062      7343.620    1.000        1.000 
## V27          1     22090.615         4.789      7346.348    1.000        1.000 
## V37          1     22091.312         5.429      7346.987    1.000        1.000 
## V1           1     28861.873      9781.036     17122.594    0.999        0.999 
## V2           1     36725.787     38406.186     45747.744    0.997        0.997 
## V52          1     45720.382    133436.683    140778.242    0.992        0.992 
## V51          1     48716.081    197360.307    204701.865    0.989        0.989 
## V17          1     58503.869    688221.925    695563.484    0.961        0.961 
## V11          1     58592.174    695940.274    703281.832    0.961        0.961 
## V18          1     58657.686    701721.675    709063.234    0.961        0.961 
## V4           1     58658.091    701757.573    709099.132    0.961        0.961 
## V12          1     58726.541    707849.244    715190.803    0.960        0.960 
## V10          1     58802.869    714703.841    722045.399    0.960        0.960 
## V19          1     58843.466    718376.307    725717.865    0.960        0.960 
## V6           1     58844.123    718435.913    725777.471    0.960        0.960 
## V3           1     58913.472    724753.134    732094.693    0.959        0.959 
## V7           1     58918.709    725232.491    732574.049    0.959        0.959 
## V20          1     58924.210    725736.245    733077.803    0.959        0.959 
## V8           1     58924.699    725781.049    733122.608    0.959        0.959 
## V14          1     58954.334    728501.148    735842.706    0.959        0.959 
## V13          1     58964.922    729475.401    736816.959    0.959        0.959 
## V9           1     58965.811    729557.288    736898.847    0.959        0.959 
## V15          1     58967.359    729699.907    737041.466    0.959        0.959 
## V16          1     58996.006    732343.244    739684.802    0.959        0.959 
## V5           1     59039.227    736349.285    743690.843    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V22 
## 
## 
##   Step 21 : AIC = 22085.96 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V24 + V27 + V33 + V36 + V37 + V42 + V44 + V47 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V44          1     22084.714         0.688      7342.767    1.000        1.000 
## V50          1     22084.875         0.837      7342.915    1.000        1.000 
## V47          1     22084.961         0.915      7342.994    1.000        1.000 
## V36          1     22085.099         1.042      7343.120    1.000        1.000 
## V33          1     22085.572         1.476      7343.554    1.000        1.000 
## V42          1     22086.089         1.950      7344.029    1.000        1.000 
## V24          1     22086.181         2.035      7344.113    1.000        1.000 
## V27          1     22089.184         4.792      7346.870    1.000        1.000 
## V37          1     22089.872         5.423      7347.501    1.000        1.000 
## V1           1     28860.852      9782.611     17124.690    0.999        0.999 
## V2           1     36724.248     38408.304     45750.383    0.997        0.997 
## V52          1     45718.413    133436.699    140778.777    0.992        0.992 
## V51          1     48714.253    197364.202    204706.280    0.989        0.989 
## V17          1     58503.599    688371.840    695713.918    0.961        0.961 
## V11          1     58591.054    696017.121    703359.199    0.961        0.961 
## V18          1     58655.933    701743.034    709085.113    0.961        0.961 
## V4           1     58656.268    701772.700    709114.778    0.961        0.961 
## V12          1     58724.816    707873.335    715215.414    0.960        0.960 
## V10          1     58802.031    714808.195    722150.273    0.960        0.960 
## V6           1     58842.185    718441.021    725783.099    0.960        0.960 
## V19          1     58842.253    718447.220    725789.298    0.960        0.960 
## V3           1     58912.638    724859.313    732201.392    0.959        0.959 
## V7           1     58916.964    725255.288    732597.366    0.959        0.959 
## V8           1     58922.834    725792.911    733134.989    0.959        0.959 
## V20          1     58925.065    725997.278    733339.356    0.959        0.959 
## V14          1     58952.881    728550.985    735893.063    0.959        0.959 
## V13          1     58962.929    729475.577    736817.655    0.959        0.959 
## V9           1     58963.811    729556.776    736898.855    0.959        0.959 
## V15          1     58967.020    729852.365    737194.444    0.959        0.959 
## V16          1     58994.153    732356.250    739698.328    0.959        0.959 
## V5           1     59037.918    736412.997    743755.075    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V44 
## 
## 
##   Step 22 : AIC = 22084.71 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V24 + V27 + V33 + V36 + V37 + V42 + V47 + V50 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V50          1     22083.645         0.854      7343.621    1.000        1.000 
## V47          1     22083.726         0.928      7343.695    1.000        1.000 
## V36          1     22083.835         1.029      7343.796    1.000        1.000 
## V33          1     22084.301         1.456      7344.223    1.000        1.000 
## V42          1     22084.809         1.923      7344.690    1.000        1.000 
## V24          1     22084.892         1.999      7344.766    1.000        1.000 
## V27          1     22087.933         4.791      7347.558    1.000        1.000 
## V37          1     22088.649         5.448      7348.215    1.000        1.000 
## V1           1     28859.027      9782.297     17125.064    0.999        0.999 
## V2           1     36722.556     38409.374     45752.141    0.997        0.997 
## V52          1     45717.071    133447.597    140790.364    0.992        0.992 
## V51          1     48712.255    197363.567    204706.334    0.989        0.989 
## V17          1     58502.264    688428.997    695771.764    0.961        0.961 
## V11          1     58589.283    696036.543    703379.309    0.961        0.961 
## V4           1     58654.276    701772.750    709115.516    0.961        0.961 
## V18          1     58657.209    702032.683    709375.450    0.961        0.961 
## V12          1     58723.032    707891.952    715234.718    0.960        0.960 
## V10          1     58800.197    714822.486    722165.253    0.960        0.960 
## V6           1     58840.441    718463.564    725806.331    0.960        0.960 
## V19          1     58840.625    718480.247    725823.014    0.960        0.960 
## V3           1     58911.809    724965.836    732308.602    0.959        0.959 
## V7           1     58915.028    725260.460    732603.227    0.959        0.959 
## V8           1     58920.993    725806.748    733149.514    0.959        0.959 
## V20          1     58923.330    726020.907    733363.674    0.959        0.959 
## V14          1     58950.909    728552.816    735895.583    0.959        0.959 
## V13          1     58961.047    729485.776    736828.543    0.959        0.959 
## V9           1     58964.178    729774.111    737116.878    0.959        0.959 
## V15          1     58965.353    729882.379    737225.146    0.959        0.959 
## V16          1     58992.208    732360.635    739703.402    0.959        0.959 
## V5           1     59037.880    736594.673    743937.439    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V50 
## 
## 
##   Step 23 : AIC = 22083.64 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V24 + V27 + V33 + V36 + V37 + V42 + V47 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V47          1     22082.670         0.941      7344.562    1.000        1.000 
## V36          1     22082.687         0.956      7344.577    1.000        1.000 
## V33          1     22083.256         1.478      7345.099    1.000        1.000 
## V42          1     22083.734         1.917      7345.538    1.000        1.000 
## V24          1     22083.782         1.962      7345.583    1.000        1.000 
## V27          1     22086.844         4.773      7348.394    1.000        1.000 
## V37          1     22087.588         5.456      7349.077    1.000        1.000 
## V1           1     28857.503      9782.463     17126.084    0.999        0.999 
## V2           1     36721.461     38413.696     45757.317    0.997        0.997 
## V52          1     45716.707    133475.521    140819.142    0.992        0.992 
## V51          1     48710.546    197370.134    204713.755    0.989        0.989 
## V17          1     58501.366    688523.945    695867.566    0.961        0.961 
## V11          1     58587.288    696036.166    703379.787    0.961        0.961 
## V4           1     58652.949    701831.501    709175.122    0.961        0.961 
## V18          1     58655.210    702031.940    709375.561    0.961        0.961 
## V12          1     58726.463    708376.692    715720.313    0.960        0.960 
## V10          1     58799.318    714922.822    722266.443    0.960        0.960 
## V19          1     58838.822    718497.300    725840.921    0.960        0.960 
## V6           1     58838.896    718503.998    725847.619    0.960        0.960 
## V3           1     58910.489    725027.211    732370.832    0.959        0.959 
## V7           1     58913.049    725261.540    732605.161    0.959        0.959 
## V8           1     58919.396    725842.859    733186.480    0.959        0.959 
## V20          1     58921.515    726037.062    733380.683    0.959        0.959 
## V14          1     58949.228    728581.270    735924.891    0.959        0.959 
## V13          1     58959.172    729496.443    736840.064    0.959        0.959 
## V9           1     58962.230    729778.016    737121.637    0.959        0.959 
## V15          1     58963.370    729883.019    737226.640    0.959        0.959 
## V16          1     58990.449    732382.087    739725.708    0.959        0.959 
## V5           1     59036.931    736691.465    744035.086    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V47 
## 
## 
##   Step 24 : AIC = 22082.67 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V24 + V27 + V33 + V36 + V37 + V42 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V36          1     22081.708         0.952      7345.514    1.000        1.000 
## V33          1     22082.283         1.480      7346.042    1.000        1.000 
## V42          1     22082.742         1.902      7346.464    1.000        1.000 
## V24          1     22082.778         1.935      7346.497    1.000        1.000 
## V27          1     22085.913         4.814      7349.376    1.000        1.000 
## V37          1     22086.649         5.490      7350.052    1.000        1.000 
## V1           1     28855.756      9782.063     17126.625    0.999        0.999 
## V2           1     36722.643     38430.951     45775.513    0.997        0.997 
## V52          1     45714.717    133474.761    140819.323    0.992        0.992 
## V51          1     48708.931    197379.063    204723.625    0.989        0.989 
## V17          1     58501.271    688688.716    696033.279    0.961        0.961 
## V11          1     58585.356    696041.164    703385.726    0.961        0.961 
## V4           1     58651.190    701851.902    709196.464    0.961        0.961 
## V18          1     58653.549    702060.989    709405.551    0.961        0.961 
## V12          1     58724.660    708393.327    715737.889    0.960        0.960 
## V10          1     58797.887    714973.166    722317.728    0.960        0.960 
## V6           1     58837.471    718555.144    725899.706    0.960        0.960 
## V19          1     58839.417    718731.769    726076.331    0.960        0.960 
## V3           1     58908.550    725031.788    732376.350    0.959        0.959 
## V7           1     58912.539    725397.005    732741.567    0.959        0.959 
## V8           1     58919.046    725993.114    733337.676    0.959        0.959 
## V20          1     58920.641    726139.278    733483.840    0.959        0.959 
## V14          1     58947.361    728592.555    735937.117    0.959        0.959 
## V13          1     58957.368    729513.477    736858.039    0.959        0.959 
## V9           1     58960.753    729825.321    737169.883    0.959        0.959 
## V15          1     58961.599    729903.241    737247.803    0.959        0.959 
## V16          1     58988.664    732400.996    739745.558    0.959        0.959 
## V5           1     59038.586    737030.456    744375.018    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V36 
## 
## 
##   Step 25 : AIC = 22081.71 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V24 + V27 + V33 + V37 + V42 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V33          1     22081.363         1.519      7347.034    1.000        1.000 
## V42          1     22081.775         1.898      7347.413    1.000        1.000 
## V24          1     22081.818         1.937      7347.452    1.000        1.000 
## V27          1     22084.906         4.773      7350.287    1.000        1.000 
## V37          1     22085.656         5.462      7350.976    1.000        1.000 
## V1           1     28853.992      9781.616     17127.131    0.999        0.999 
## V2           1     36720.738     38430.543     45776.057    0.997        0.997 
## V52          1     45715.786    133527.824    140873.338    0.992        0.992 
## V51          1     48708.705    197423.493    204769.007    0.989        0.989 
## V17          1     58500.142    688763.452    696108.966    0.961        0.961 
## V11          1     58583.364    696040.943    703386.457    0.961        0.961 
## V4           1     58650.905    702002.937    709348.451    0.961        0.961 
## V18          1     58651.624    702066.710    709412.225    0.961        0.961 
## V12          1     58723.282    708448.041    715793.555    0.960        0.960 
## V10          1     58796.124    714993.676    722339.190    0.960        0.960 
## V6           1     58835.805    718584.490    725930.004    0.960        0.960 
## V19          1     58837.435    718732.463    726077.978    0.960        0.960 
## V3           1     58908.255    725186.923    732532.437    0.959        0.959 
## V7           1     58910.700    725410.770    732756.284    0.959        0.959 
## V8           1     58917.567    726039.848    733385.363    0.959        0.959 
## V20          1     58918.865    726158.899    733504.413    0.959        0.959 
## V14          1     58945.539    728607.988    735953.502    0.959        0.959 
## V13          1     58957.289    729689.484    737034.998    0.959        0.959 
## V9           1     58958.933    729840.894    737186.408    0.959        0.959 
## V15          1     58960.592    729993.805    737339.319    0.959        0.959 
## V16          1     58986.807    732413.334    739758.848    0.959        0.959 
## V5           1     59036.602    737031.043    744376.557    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## - V33 
## 
## 
##   Step 26 : AIC = 22081.36 
##  Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V18 + V19 + V20 + V24 + V27 + V37 + V42 + V51 + V52 
## 
## ------------------------------------------------------------------------------
## Variable     DF       AIC         Sum Sq         RSS        R-Sq     Adj. R-Sq 
## ------------------------------------------------------------------------------
## V24          1     22081.466         1.931      7348.965    1.000        1.000 
## V42          1     22081.467         1.932      7348.966    1.000        1.000 
## V27          1     22084.473         4.693      7351.727    1.000        1.000 
## V37          1     22085.218         5.378      7352.412    1.000        1.000 
## V1           1     28855.096      9786.740     17133.774    0.999        0.999 
## V2           1     36718.749     38429.085     45776.119    0.997        0.997 
## V52          1     45714.676    133541.982    140889.016    0.992        0.992 
## V51          1     48707.736    197448.358    204795.392    0.989        0.989 
## V17          1     58501.102    689019.511    696366.545    0.961        0.961 
## V11          1     58583.608    696236.658    703583.692    0.961        0.961 
## V4           1     58649.543    702058.005    709405.039    0.961        0.961 
## V18          1     58651.176    702202.779    709549.813    0.961        0.961 
## V12          1     58721.332    708451.013    715798.047    0.960        0.960 
## V10          1     58794.320    715009.805    722356.839    0.960        0.960 
## V6           1     58833.858    718587.792    725934.825    0.960        0.960 
## V19          1     58836.440    718822.095    726169.129    0.960        0.960 
## V7           1     58908.705    725409.736    732756.770    0.959        0.959 
## V3           1     58909.132    725448.877    732795.911    0.959        0.959 
## V8           1     58915.631    726044.255    733391.289    0.959        0.959 
## V20          1     58918.111    726271.583    733618.616    0.959        0.959 
## V14          1     58943.649    728616.588    735963.622    0.959        0.959 
## V13          1     58956.047    729757.776    737104.810    0.959        0.959 
## V9           1     58956.992    729844.809    737191.843    0.959        0.959 
## V15          1     58958.808    730012.154    737359.188    0.959        0.959 
## V16          1     58984.936    732423.718    739770.752    0.959        0.959 
## V5           1     59034.681    737036.816    744383.850    0.959        0.959 
## ------------------------------------------------------------------------------
## 
## 
## No more variables to be removed.
## 
## Variables Removed: 
## 
## - V32 
## - V26 
## - V40 
## - V46 
## - V41 
## - V28 
## - V31 
## - V34 
## - V38 
## - V39 
## - V23 
## - V48 
## - V25 
## - V30 
## - V43 
## - V45 
## - V35 
## - V29 
## - V21 
## - V49 
## - V22 
## - V44 
## - V50 
## - V47 
## - V36 
## - V33 
## 
## 
## Final Model Output 
## ------------------
## 
##                         Model Summary                         
## -------------------------------------------------------------
## R                       1.000       RMSE               0.960 
## R-Squared               1.000       Coef. Var          0.190 
## Adj. R-Squared          1.000       MSE                0.921 
## Pred R-Squared          1.000       MAE                0.697 
## -------------------------------------------------------------
##  RMSE: Root Mean Square Error 
##  MSE: Mean Square Error 
##  MAE: Mean Absolute Error 
## 
##                                     ANOVA                                      
## ------------------------------------------------------------------------------
##                     Sum of                                                    
##                    Squares          DF    Mean Square        F           Sig. 
## ------------------------------------------------------------------------------
## Regression    18028630.897          26     693408.881    752675.962    0.0000 
## Residual          7347.034        7975          0.921                         
## Total         18035977.931        8001                                        
## ------------------------------------------------------------------------------
## 
##                                    Parameter Estimates                                     
## ------------------------------------------------------------------------------------------
##       model      Beta    Std. Error    Std. Beta       t         Sig      lower     upper 
## ------------------------------------------------------------------------------------------
## (Intercept)     2.601         0.185                   14.073    0.000     2.238     2.963 
##          V1     3.449         0.033        0.199     103.069    0.000     3.383     3.514 
##          V2     3.496         0.017        0.157     204.239    0.000     3.462     3.529 
##          V3     3.493         0.004        0.201     887.386    0.000     3.485     3.501 
##          V4     3.494         0.004        0.197     872.963    0.000     3.487     3.502 
##          V5     3.502         0.004        0.202     894.446    0.000     3.495     3.510 
##          V6     3.500         0.004        0.200     883.180    0.000     3.493     3.508 
##          V7     3.506         0.004        0.201     887.362    0.000     3.498     3.513 
##          V8     3.498         0.004        0.201     887.750    0.000     3.490     3.506 
##          V9     3.500         0.004        0.202     890.071    0.000     3.492     3.507 
##         V10     3.496         0.004        0.199     880.979    0.000     3.488     3.504 
##         V11     3.501         0.004        0.197     869.336    0.000     3.493     3.509 
##         V12     3.509         0.004        0.199     876.929    0.000     3.501     3.516 
##         V13     3.499         0.004        0.201     890.018    0.000     3.492     3.507 
##         V14     3.501         0.004        0.201     889.322    0.000     3.493     3.508 
##         V15     3.502         0.004        0.201     890.173    0.000     3.494     3.510 
##         V16     3.501         0.004        0.202     891.642    0.000     3.494     3.509 
##         V17     3.491         0.004        0.196     864.819    0.000     3.483     3.499 
##         V18     3.505         0.004        0.198     873.053    0.000     3.497     3.513 
##         V19     3.502         0.004        0.200     883.324    0.000     3.495     3.510 
##         V20     3.495         0.004        0.201     887.889    0.000     3.488     3.503 
##         V24    -0.006         0.004        0.000      -1.448    0.148    -0.014     0.002 
##         V27    -0.009         0.004       -0.001      -2.257    0.024    -0.017    -0.001 
##         V37    -0.009         0.004       -0.001      -2.416    0.016    -0.017    -0.002 
##         V42    -0.006         0.004        0.000      -1.448    0.148    -0.014     0.002 
##         V51    -4.488         0.010       -0.914    -462.952    0.000    -4.507    -4.469 
##         V52    -4.517         0.012       -0.193    -380.731    0.000    -4.540    -4.493 
## ------------------------------------------------------------------------------------------
mod_bcwd
## 
## 
##                         Backward Elimination Summary                         
## ---------------------------------------------------------------------------
## Variable         AIC         RSS          Sum Sq        R-Sq      Adj. R-Sq 
## ---------------------------------------------------------------------------
## Full Model    22123.582    7338.059    18028639.872    0.99959      0.99959 
## V32           22121.582    7338.059    18028639.871    0.99959      0.99959 
## V26           22119.585    7338.062    18028639.868    0.99959      0.99959 
## V40           22117.602    7338.078    18028639.853    0.99959      0.99959 
## V46           22115.632    7338.105    18028639.826    0.99959      0.99959 
## V41           22113.684    7338.153    18028639.778    0.99959      0.99959 
## V28           22111.738    7338.202    18028639.728    0.99959      0.99959 
## V31           22109.797    7338.256    18028639.675    0.99959      0.99959 
## V34           22107.861    7338.315    18028639.616    0.99959      0.99959 
## V38           22105.995    7338.438    18028639.493    0.99959      0.99959 
## V39           22104.134    7338.565    18028639.365    0.99959      0.99959 
## V23           22102.278    7338.697    18028639.233    0.99959      0.99959 
## V48           22100.451    7338.856    18028639.075    0.99959      0.99959 
## V25           22098.677    7339.064    18028638.867    0.99959      0.99959 
## V30           22096.922    7339.288    18028638.643    0.99959      0.99959 
## V43           22095.186    7339.530    18028638.400    0.99959      0.99959 
## V45           22093.526    7339.842    18028638.088    0.99959      0.99959 
## V35           22091.932    7340.214    18028637.716    0.99959      0.99959 
## V29           22090.383    7340.628    18028637.303    0.99959      0.99959 
## V21           22088.876    7341.080    18028636.850    0.99959      0.99959 
## V49           22087.397    7341.558    18028636.372    0.99959      0.99959 
## V22           22085.964    7342.078    18028635.852    0.99959      0.99959 
## V44           22084.714    7342.767    18028635.164    0.99959      0.99959 
## V50           22083.645    7343.621    18028634.310    0.99959      0.99959 
## V47           22082.670    7344.562    18028633.369    0.99959      0.99959 
## V36           22081.708    7345.514    18028632.416    0.99959      0.99959 
## V33           22081.363    7347.034    18028630.897    0.99959      0.99959 
## ---------------------------------------------------------------------------
mod_bcwd$model
## 
## Call:
## lm(formula = paste(response, "~", paste(preds, collapse = " + ")), 
##     data = l)
## 
## Coefficients:
## (Intercept)           V1           V2           V3           V4           V5  
##    2.600549     3.448787     3.495759     3.493128     3.494456     3.502448  
##          V6           V7           V8           V9          V10          V11  
##    3.500391     3.505625     3.497991     3.499672     3.495768     3.501190  
##         V12          V13          V14          V15          V16          V17  
##    3.508631     3.499304     3.500580     3.501821     3.501314     3.491392  
##         V18          V19          V20          V24          V27          V37  
##    3.505106     3.502441     3.495246    -0.005822    -0.008911    -0.009406  
##         V42          V51          V52  
##   -0.005739    -4.487634    -4.516698

Model terbaik hasil dari seleksi peubah

#Best Model
best_model<-lm(formula = Y~ V1 + V2 + V3  + V4  + V5  + V6  + V7  + V8  + V9  + V10  + V11  + V12  + V13  + V14  + V15  + V16  + V17  + V19  + V20 + V29  + V31  + V33  + V34  + V51  + V52, data = train.dataindex)

summary(best_model)
## 
## Call:
## lm(formula = Y ~ V1 + V2 + V3 + V4 + V5 + V6 + V7 + V8 + V9 + 
##     V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + V19 + V20 + 
##     V29 + V31 + V33 + V34 + V51 + V52, data = train.dataindex)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -34.595  -6.107  -0.136   6.130  39.781 
## 
## Coefficients:
##              Estimate Std. Error t value Pr(>|t|)    
## (Intercept) 34.894878   1.769971  19.715   <2e-16 ***
## V1           3.415615   0.328894  10.385   <2e-16 ***
## V2           3.291052   0.168179  19.569   <2e-16 ***
## V3           3.472381   0.038690  89.748   <2e-16 ***
## V4           3.484619   0.039349  88.557   <2e-16 ***
## V5           3.462220   0.038486  89.960   <2e-16 ***
## V6           3.568112   0.038953  91.600   <2e-16 ***
## V7           3.509518   0.038809  90.431   <2e-16 ***
## V8           3.493387   0.038720  90.221   <2e-16 ***
## V9           3.485065   0.038637  90.201   <2e-16 ***
## V10          3.548815   0.038991  91.016   <2e-16 ***
## V11          3.496363   0.039586  88.323   <2e-16 ***
## V12          3.479025   0.039314  88.493   <2e-16 ***
## V13          3.478814   0.038643  90.024   <2e-16 ***
## V14          3.595009   0.038670  92.967   <2e-16 ***
## V15          3.503096   0.038664  90.603   <2e-16 ***
## V16          3.510310   0.038592  90.959   <2e-16 ***
## V17          3.454014   0.039676  87.055   <2e-16 ***
## V19          3.495332   0.038965  89.705   <2e-16 ***
## V20          3.513663   0.038701  90.789   <2e-16 ***
## V29         -0.006534   0.038762  -0.169    0.866    
## V31          0.039644   0.038869   1.020    0.308    
## V33         -0.049770   0.039045  -1.275    0.202    
## V34         -0.003863   0.039004  -0.099    0.921    
## V51         -4.440976   0.095262 -46.619   <2e-16 ***
## V52         -4.646754   0.116594 -39.854   <2e-16 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 9.434 on 7976 degrees of freedom
## Multiple R-squared:  0.9606, Adjusted R-squared:  0.9605 
## F-statistic:  7788 on 25 and 7976 DF,  p-value: < 2.2e-16

Uji Asumsi Regresi

Dalam membangun model regresi linier, metode estimasi yang digunakan adalah dengan metode estimasi kuadrat terkecil (ordinary least square), yaitu dengan meminimumkan jumlah kuadrat residual.

Terdapat asumsi yang harus diuji dalam membangun model regresi linier tersebut. Asumsi model tersebut sering juga disebut sebagai asumsi klasik yang terdiri atas :

  • Uji normalitas residual
  • Uji asumsi variasi galat yang bersifat konstan (homoskedastisitas)
  • Uji asumsi tidak adanya serial korelasi dari galat (autokorelasi)
  • Uji multikolinieritas antarvariabel independen.

Uji Kenormalan

Kenormalan sisaan akan diuji dengan Uji Jarque Bera

#Normalitas residual
jarque.bera.test(best_model$residuals)
## 
##  Jarque Bera Test
## 
## data:  best_model$residuals
## X-squared = 0.56363, df = 2, p-value = 0.7544

Hipotesis

H0 : Residual berdistribusi normal H1 : Residual tidak berdistribusi normal

Tingkat signifikansi = 0.05

Statistik Uji : p-value = 0.2272

Keputusan : Karena p-value (0.2272) > alpha (0.05), maka gagal tolak H0

Kesimpulan : Dengan tingkat keyakinan 95%, kita yakin bahwa residual berdistribusi normal.

Uji Homogenitas

Untuk menguji homoskedastisitas akan digunakan uji Breusch Pagan

#Kehomogenan Ragam
bptest(best_model, data=DAT.SIM.01)
## 
##  studentized Breusch-Pagan test
## 
## data:  best_model
## BP = 22.443, df = 25, p-value = 0.61

Hipotesis

H0 : Ragam Homogen H1 : Ragam tidak homogen

Tingkat Signifikansi : 0.05

Statistik Uji : pvalue = 0.2382

Keputusan : Karena p-value (0.2382) > alpha (0.05) maka gagal tolak H0.

Kesimpulan : Dengan tingkat keyakinan 95%, kita yakin bahwa ragam homogen (asumsi homoskedastisitas terpenuhi)

Uji Autokorelasi

Uji autokorelasi akan diuji dengan uji Durbin Watson

#Autokorelasi
dwtest(best_model)
## 
##  Durbin-Watson test
## 
## data:  best_model
## DW = 2.0156, p-value = 0.7582
## alternative hypothesis: true autocorrelation is greater than 0

Hipotesis

H0 : Tidak ada auto korelasi dari galat H1 : Ada auto korelasi dari galat

Tingkat signifikansi : 0.05

Statistik uji : pvalue = 0.8405

Keputusan : Karena nilai pvalue (0.8405) > alpha (0.05) maka gagal tolak H0

Kesimpulan : Dengan tingkat kepercayaan 95%, kita yakin bahwa tidak ada auto korelasi pada galat.

Uji Multikolinieritas

Kolinieritas akan diuji dengan VIF (Variance Inflation Factor). Jika, nilai VIF > 5, maka terjadi multikolinieritas.

#Uji Multikolinieritas
vif(best_model)
##        V1        V2        V3        V4        V5        V6        V7        V8 
## 72.743941 11.632354  1.003192  1.001745  1.001515  1.003058  1.002405  1.003114 
##        V9       V10       V11       V12       V13       V14       V15       V16 
##  1.003211  1.002175  1.004354  1.002672  1.003300  1.003109  1.002121  1.001747 
##       V17       V19       V20       V29       V31       V33       V34       V51 
##  1.001989  1.001678  1.002443  1.001743  1.002903  1.002402  1.002231 76.260358 
##       V52 
##  5.028906

Variabel V1,V2,V51,dan V52 memiliki nilai VIF > 5 dan nilainya sangat besar sehingga mengindikasikan bahwa ada multikolinieritas

Cek Korelasi Variabel

Uji multikolinieritas dengan VIF > 5 menunjukkan adanya multikolinieritas. Pada data juga sudah diketahui bahwa ada 4 variabel yang berkorelasi kuat. Akan diuji variabel mana yang berkorelasi dengan menggunakan matrik korelasi

#Cek korelasi
data_kor <- train.dataindex[c(2,3,52,53)]

mk <- cor(data_kor)

round(mk,2) #Membulatkan 2 angka di belakang koma
##        V1    V2   V51   V52
## V1   1.00  0.94  0.98 -0.59
## V2   0.94  1.00  0.93 -0.62
## V51  0.98  0.93  1.00 -0.45
## V52 -0.59 -0.62 -0.45  1.00
corrplot(mk, type="lower",
         order = "hclust", # mengurutkan berdasarkan hierarchical clustering
         tl.col= "black", # warna tulisan
         addCoef.col = "black", # tambahkan koefisien korelasi
         diag=FALSE, #menyembunyikan koefisien pada diagonal
         tl.srt= 45, # kemiringan tulisan 45 derajat
         method = "circle") # Bentuk Visualisasi

Terlihat dalam matriks korelasi bahwa terdapat korelasi yang tinggi antara V1 dan V2, V51 dam V2, V51 dan V1, V52 dam V1, V52 dan V2 yang menyebabkan adanya kolinieritas. Solusi dari masalah ini bisa diselesaikan dengan beberapa cara yaitu menghilangkan variabel yang berkorelasi atau menggunakan metode penyusutan peubah dengan ridge, lasso, dan elastic-net. Pada bahasan kali ini kit akan selesaikan masalah tsb dengan metode ridge, lasso, dan elastic-net.

Prediksi data

Selanjutnya kita akan mencoba model best-subset yang sudah dibuat dengan menggunakan data test.

preds_best <- predict(best_model, test.dataindex)
head(preds_best)
##       18       19       30       37       38       40 
## 590.4094 518.2193 519.5790 501.0044 483.8206 527.5415

Melihat akurasi prediksi dengan menggunakan plot

plot(test.dataindex$Y, preds_best, col = "blue")

cor(test.dataindex$Y, preds_best)
## [1] 0.9801524

Shrinkage Method

Regresi Shrinkage merupakan model regresi yang menggunakan suatu penalty tertentu saat melakukan estimasi koefisienya. Penalti tersebut berperan untuk seleksi peubah ataupun mengatasi kolinear yang tinggi antar peubah prediktor. Model-model untuk yang termasuk dalam regresi shirnkage antara lain:

Regresi LASSO

Regresi Ridge

Regresi Elastic Net

Regresi Lasso

Metode pertama yang kita coba adalah metode LASSO. Metode ini bisa dijalankan menggunakan package glmnet. Package glmnetUtils merupakan package tambahan dari glmnet yang memungkinkan syntax glmnet bisa dinput menggunakan object data.frame.

Fungsi cv.glmnet digunakan untuk menjalankan menjalankan metode LASSO, asalkan nilai argumen alpha=1. Kemudian, dengan fungsi ini juga dimungkinkan memilih parameter penalty lambda terbaik dengan menggunakan cross-validation (validasi-silang) yang didasarkan pada kriteria tertentu, contohnya saja kriteria “mse” dan “mae”. Proses ini disebut juga sebagai Tuning Parameter. Dimana lambda merupakan parameter yang akan dicari nilai optimalnya berdasarkan nilai kebaikan model “mse” dan “mae”. Argumen nfolds digunakan untuk menentukan jumlah folds/lipatan pada cross-validation.

set.seed(123)

model_lasso_mae <- cv.glmnet(Y~.,data=train.dataindex,alpha = 1,
                         type.measure="mae",
                         family="gaussian",
                         nfolds=5)

Melihat jumlah variabel terbaik berdasarkan metode ini

plot(model_lasso_mae)

Informasi penting yang bisa dilihat pada plot diatas adalah banyaknya peubah terpilih yang ditulis diatas plot. Kemudian ada garis vertikal putus-putus yang menandakan nilai lambda optimum berdasarkan kriteria yang dipilih. Nilai lambda optimum dipilih berdasarkan nilai mae terkecil. Selain itu, kriteria lambda optimum juga dipilih berdasarkan lembar selang terkecil dari garis pada setiap titik. Sehingga garis vertikal yang satunya menandakan hal tersebut. Informasi ini akan lebih jelas dengan bantuan package broom.

info_lasso_mae <- broom::glance(model_lasso_mae)
info_lasso_mae
broom::tidy(model_lasso_mae)

Nilai koefisien dari variable terpilih bisa dikeluarkan dengan bantuan package broom dibawah ini.

broom::tidy(model_lasso_mae$glmnet.fit)
coef_mae_min <- broom::tidy(model_lasso_mae$glmnet.fit) %>% filter(lambda==info_lasso_mae$lambda.min)
coef_mae_min

Membangun model regresi lasso berdasarkan lambda min.

lasso_model <- glmnet(Y~.,data=train.dataindex, lambda = model_lasso_mae$lambda.min , alpha = 1)
coef(lasso_model)
## 53 x 1 sparse Matrix of class "dgCMatrix"
##                     s0
## (Intercept)  4.3764553
## V1           0.4528286
## V2           2.6493657
## V3           3.4631971
## V4           3.4804307
## V5           3.4800410
## V6           3.4825433
## V7           3.4898556
## V8           3.4743504
## V9           3.4763583
## V10          3.4775971
## V11          3.4713200
## V12          3.4911718
## V13          3.4726461
## V14          3.4785644
## V15          3.4828477
## V16          3.4811897
## V17          3.4687857
## V18          3.4831842
## V19          3.4845621
## V20          3.4809565
## V21          .        
## V22          .        
## V23          .        
## V24          .        
## V25          .        
## V26          .        
## V27          .        
## V28          .        
## V29          .        
## V30          .        
## V31          .        
## V32          .        
## V33          .        
## V34          .        
## V35          .        
## V36          .        
## V37          .        
## V38          .        
## V39          .        
## V40          .        
## V41          .        
## V42          .        
## V43          .        
## V44          .        
## V45          .        
## V46          .        
## V47          .        
## V48          .        
## V49          .        
## V50          .        
## V51         -3.5661917
## V52         -5.4382644

Prediksi data test dengan menggunakan model lasso

preds_lasso <- predict(lasso_model, test.dataindex)
head(preds_lasso)
##            s0
## [1,] 595.0505
## [2,] 519.1783
## [3,] 533.6368
## [4,] 500.0377
## [5,] 508.8978
## [6,] 526.6427

Melihat akurasi prediksi dengan menggunakan plot

plot(test.dataindex$Y, preds_lasso, col = "blue")

cor(test.dataindex$Y, preds_lasso)
##             s0
## [1,] 0.9995587

Regresi Ridge

Metode kedua yang kita coba adalah metode RIDGE. Metode ini bisa dijalankan menggunakan package glmnet. Package glmnetUtils merupakan package tambahan dari glmnet yang memungkinkan syntax glmnet bisa dinput menggunakan object data.frame.

Fungsi cv.glmnet digunakan untuk menjalankan menjalankan metode RIDGE, asalkan nilai argumen alpha=0. Kemudian, dengan fungsi ini juga dimungkinkan memilih parameter penalty lambda terbaik dengan menggunakan cross-validation (validasi-silang) yang didasarkan pada kriteria tertentu, contohnya saja kriteria “mse” dan “mae”. Proses ini disebut juga sebagai Tuning Parameter. Dimana lambda merupakan parameter yang akan dicari nilai optimalnya berdasarkan nilai kebaikan model “mse” dan “mae”. Argumen nfolds digunakan untuk menentukan jumlah folds/lipatan pada cross-validation.

set.seed(123)

model_ridge_mae <- cv.glmnet(Y~.,data=train.dataindex,alpha =0, type.measure="mae",family="gaussian",nfolds=5)
plot(model_ridge_mae)

info_ridge_mae <- broom::glance(model_ridge_mae)
info_ridge_mae
broom::tidy(model_ridge_mae)
broom::tidy(model_ridge_mae$glmnet.fit)
ridge_mae_min <- broom::tidy(model_ridge_mae$glmnet.fit) %>% filter(lambda==info_ridge_mae$lambda.min)
ridge_mae_min
ridge_model <- glmnet(Y~.,data=train.dataindex, lambda = model_ridge_mae$lambda.min , alpha = 0)
coef(ridge_model)
## 53 x 1 sparse Matrix of class "dgCMatrix"
##                        s0
## (Intercept)  2.223285e+01
## V1          -3.507508e+00
## V2          -1.935697e-01
## V3           3.302955e+00
## V4           3.343847e+00
## V5           3.324738e+00
## V6           3.332249e+00
## V7           3.353683e+00
## V8           3.317098e+00
## V9           3.323868e+00
## V10          3.335864e+00
## V11          3.311649e+00
## V12          3.345863e+00
## V13          3.325702e+00
## V14          3.338579e+00
## V15          3.346638e+00
## V16          3.334999e+00
## V17          3.329315e+00
## V18          3.338619e+00
## V19          3.339188e+00
## V20          3.340788e+00
## V21          1.051328e-02
## V22          8.004975e-03
## V23          1.632594e-02
## V24         -4.153250e-03
## V25         -7.018265e-03
## V26         -7.532913e-03
## V27          3.843484e-03
## V28          5.672893e-05
## V29         -4.221685e-03
## V30          2.282977e-02
## V31         -2.983686e-03
## V32         -3.512919e-03
## V33         -2.924336e-03
## V34          1.738675e-02
## V35          3.261770e-02
## V36         -3.663143e-03
## V37          4.760438e-03
## V38          1.504364e-02
## V39          1.506062e-02
## V40         -6.978834e-03
## V41          1.216738e-02
## V42          9.709148e-03
## V43          6.781041e-04
## V44         -9.624483e-03
## V45         -1.602049e-02
## V46          6.368778e-03
## V47         -7.136294e-03
## V48          4.778305e-03
## V49          6.941383e-03
## V50          2.087898e-02
## V51         -1.907352e+00
## V52         -6.582305e+00
preds_ridge <- predict(ridge_model, test.dataindex)
head(preds_ridge)
##            s0
## [1,] 590.4440
## [2,] 519.4716
## [3,] 534.2941
## [4,] 501.1628
## [5,] 506.6590
## [6,] 528.1139
plot(test.dataindex$Y, preds_ridge, col = "blue")

cor(test.dataindex$Y, preds_ridge)
##             s0
## [1,] 0.9977694

Regresi Elastic-net

Metode kedua yang kita coba adalah metode ELASTIC-NET. Metode ini bisa dijalankan menggunakan package glmnet. Package glmnetUtils merupakan package tambahan dari glmnet yang memungkinkan syntax glmnet bisa dinput menggunakan object data.frame.

Fungsi cv.glmnet digunakan untuk menjalankan menjalankan metode ELASTIC-NET, asalkan nilai argumen alpha=0-1. Kemudian, dengan fungsi ini juga dimungkinkan memilih parameter penalty lambda terbaik dengan menggunakan cross-validation (validasi-silang) yang didasarkan pada kriteria tertentu, contohnya saja kriteria “mse” dan “mae”. Proses ini disebut juga sebagai Tuning Parameter. Dimana lambda merupakan parameter yang akan dicari nilai optimalnya berdasarkan nilai kebaikan model “mse” dan “mae”. Argumen nfolds digunakan untuk menentukan jumlah folds/lipatan pada cross-validation.

set.seed(123)
model_elastic_mae <- cv.glmnet(Y~.,
                               data=train.dataindex ,
                               alpha = 0.8,
                               type.measure="mae",
                               family="gaussian",nfolds=5)
plot(model_elastic_mae)

info_elastic_mae <- broom::glance(model_elastic_mae)
info_elastic_mae
broom::tidy(model_elastic_mae)
broom::tidy(model_elastic_mae$glmnet.fit)
elastic_mae_min <- broom::tidy(model_elastic_mae$glmnet.fit) %>% filter(lambda==info_elastic_mae$lambda.min)
elastic_mae_min

Menghitung nilai mae model elastic-net dengan memasukkan semua nilai alpha yang mungkin.

for (i in 0:10) {
    assign(paste("fit", i, sep=""), cv.glmnet(Y~.,data=train.dataindex, type.measure="mae", alpha=i/10))
}

yhat0 <- predict(fit0, s=fit0$lambda.1se, test.dataindex)
yhat1 <- predict(fit1, s=fit1$lambda.1se, test.dataindex)
yhat2 <- predict(fit2, s=fit2$lambda.1se, test.dataindex)
yhat3 <- predict(fit3, s=fit3$lambda.1se, test.dataindex)
yhat4 <- predict(fit4, s=fit4$lambda.1se, test.dataindex)
yhat5 <- predict(fit5, s=fit5$lambda.1se, test.dataindex)
yhat6 <- predict(fit6, s=fit6$lambda.1se, test.dataindex)
yhat7 <- predict(fit7, s=fit7$lambda.1se, test.dataindex)
yhat8 <- predict(fit8, s=fit8$lambda.1se, test.dataindex)
yhat9 <- predict(fit9, s=fit9$lambda.1se, test.dataindex)
yhat10 <- predict(fit10, s=fit10$lambda.1se, test.dataindex)

mae0 <- mean(abs(test.dataindex$Y-yhat0))
mae1 <- mean(abs(test.dataindex$Y-yhat1))
mae2 <- mean(abs(test.dataindex$Y-yhat2))
mae3 <- mean(abs(test.dataindex$Y-yhat3))
mae4 <- mean(abs(test.dataindex$Y-yhat4))
mae5 <- mean(abs(test.dataindex$Y-yhat5))
mae6 <- mean(abs(test.dataindex$Y-yhat6))
mae7 <- mean(abs(test.dataindex$Y-yhat7))
mae8 <- mean(abs(test.dataindex$Y-yhat8))
mae9 <- mean(abs(test.dataindex$Y-yhat9))
mae10 <- mean(abs(test.dataindex$Y-yhat10))

alpha<-seq(0,1,by=0.1)
mae<-c(mae0,mae1,mae2,mae3,mae4,mae5,mae6,mae7,mae8,mae9,mae10)
cbind(alpha,mae)
##       alpha      mae
##  [1,]   0.0 3.068943
##  [2,]   0.1 1.171934
##  [3,]   0.2 1.174604
##  [4,]   0.3 1.176776
##  [5,]   0.4 1.181179
##  [6,]   0.5 1.163554
##  [7,]   0.6 1.164347
##  [8,]   0.7 1.177716
##  [9,]   0.8 1.144676
## [10,]   0.9 1.170801
## [11,]   1.0 1.147450
elastic_model <- glmnet(Y~.,data=train.dataindex, lambda = model_elastic_mae$lambda.min , alpha = 0.8)
coef(elastic_model)
## 53 x 1 sparse Matrix of class "dgCMatrix"
##                     s0
## (Intercept)  4.2113828
## V1           0.4621685
## V2           2.6478444
## V3           3.4641305
## V4           3.4813179
## V5           3.4809015
## V6           3.4833821
## V7           3.4907139
## V8           3.4752946
## V9           3.4772633
## V10          3.4784902
## V11          3.4723136
## V12          3.4920355
## V13          3.4736406
## V14          3.4794354
## V15          3.4836613
## V16          3.4820365
## V17          3.4697398
## V18          3.4840439
## V19          3.4854610
## V20          3.4817808
## V21          .        
## V22          .        
## V23          .        
## V24          .        
## V25          .        
## V26          .        
## V27          .        
## V28          .        
## V29          .        
## V30          .        
## V31          .        
## V32          .        
## V33          .        
## V34          .        
## V35          .        
## V36          .        
## V37          .        
## V38          .        
## V39          .        
## V40          .        
## V41          .        
## V42          .        
## V43          .        
## V44          .        
## V45          .        
## V46          .        
## V47          .        
## V48          .        
## V49          .        
## V50          .        
## V51         -3.5678512
## V52         -5.4362881
preds_elastic <- predict(elastic_model, test.dataindex)
head(preds_elastic)
##            s0
## [1,] 595.0554
## [2,] 519.1799
## [3,] 533.6335
## [4,] 500.0440
## [5,] 508.9137
## [6,] 526.6552
plot(test.dataindex$Y, preds_elastic, col = "blue")

cor(test.dataindex$Y, preds_elastic)
##             s0
## [1,] 0.9995599

Komparasi Model

Berikut ini adalah tabel komparasi dari ke-tiga metode shrinkage beserta metode best subset di atas berdasarkan nilai MAE nya.

y_test <- test.dataindex$Y

Membuat fungsi untuk hitung nilai mae

mae <- function(response,pred){
  mean(abs(response-pred),na.rm = TRUE)
}

Tabel komparasi model

mae_lasso_fnl<-mae(y_test,preds_lasso)
mae_ridge_fnl<-mae(y_test,preds_ridge)
mae_elastic_fnl<-mae(y_test,preds_elastic)
mae_best_subset<-mae(y_test,preds_best)


komparasi_mae<-as.data.frame(c(mae_ridge_fnl,mae_lasso_fnl,mae_elastic_fnl, mae_best_subset))
colnames(komparasi_mae)
## [1] "c(mae_ridge_fnl, mae_lasso_fnl, mae_elastic_fnl, mae_best_subset)"
names(komparasi_mae)[names(komparasi_mae) == "c(mae_ridge_fnl, mae_lasso_fnl, mae_elastic_fnl, mae_best_subset)"] <- "Nilai MAE"

Model<-c("Ridge", "Lasso", "Elastic-Net (0.8)", "Best-Subset")
komparasi_mae<- cbind(Model, komparasi_mae)
komparasi_mae

Kesimpulan

Berdasarkan tabel komparasi di atas, dpat disimpulkan bahwa model yang paling baik adalah model regresi elastic-net dengan nilai alpha = 0.8.

Referensi

Breheny P. (n.d.). Getting started with grpreg. GitHub Pages. https://pbreheny.github.io/grpreg/articles/getting-started.html

Hastie T. (2013, May 9). glmnet: Lasso and elastic-net regularization in R. Revolutions. https://blog.revolutionanalytics.com/2013/05/hastie-glmnet.html

Post J. (2014, September 29). LASSO, Ridge, and Elastic Net. https://www4.stat.ncsu.edu/~post/josh/LASSO_Ridge_Elastic_Net_-_Examples.html

Tibshirani, R., Saunders, M., Rosset, S., Zhu, J., & Knight, K. (2005). Sparsity and smoothness via the fused lasso. Journal of the Royal Statistical Society: Series B (Statistical Methodology), 67(1), 91-108. https://doi.org/10.1111/j.1467-9868.2005.00490.x

Tripathy A. (2013, July 14). Regularization – Predictive Modeling Beyond Ordinary Least Squares Fit. ShatterLine Blog. https://shatterline.com/blog/2013/07/

Xiaotong C., Chen G., & Chong W. (n.d.). Statistical Learning and Data Mining Codes. Biostatistics - Academic Divisions - School of Public Health - University of Minnesota. https://www.biostat.umn.edu/~weip/course/dm/examples/