library(readxl)
library(ggplot2)
library(car)
## Loading required package: carData
library(lmtest)
## Loading required package: zoo
## 
## Attaching package: 'zoo'
## The following objects are masked from 'package:base':
## 
##     as.Date, as.Date.numeric
# Dataset 1
data1 <- read_excel("Dataset 1 dan 2 Regnon.xlsx",
                    sheet = "Dataset 1")
data1
## # A tibble: 9 × 4
##       Y    X1    X2    X3
##   <dbl> <dbl> <dbl> <dbl>
## 1  57.5    78  2.75  29.5
## 2  52.8    69  2.15  26.3
## 3  61.3    77  4.41  32.2
## 4  67      88  5.52  36.5
## 5  53.5    67  3.21  27.2
## 6  62.7    80  4.32  27.7
## 7  56.2    74  2.31  28.3
## 8  68.5    94  4.3   30.3
## 9  69.2   102  3.71  28.7
## 1a. Scatter Plot X1 terhadap Y
ggplot(data1, aes(x = X1, y = Y)) +
  geom_point(size = 3) +
  geom_smooth(method = "lm", se = FALSE) +
  labs(
    title = "Scatter Plot X1 terhadap Y - Dataset 1",
    x = "X1",
    y = "Y"
  ) +
  theme_minimal()
## `geom_smooth()` using formula = 'y ~ x'

## 1b. Scatter Plot X2 terhadap Y
ggplot(data1, aes(x = X2, y = Y)) +
  geom_point(size = 3) +
  geom_smooth(method = "lm", se = FALSE) +
  labs(
    title = "Scatter Plot X2 terhadap Y - Dataset 1",
    x = "X2",
    y = "Y"
  ) +
  theme_minimal()
## `geom_smooth()` using formula = 'y ~ x'

## 1c. Scatter Plot X3 terhadap Y
ggplot(data1, aes(x = X3, y = Y)) +
  geom_point(size = 3) +
  geom_smooth(method = "lm", se = FALSE) +
  labs(
    title = "Scatter Plot X3 terhadap Y - Dataset 1",
    x = "X3",
    y = "Y"
  ) +
  theme_minimal()
## `geom_smooth()` using formula = 'y ~ x'

# ---------------
# Model 1 RLS
# ---------------

m1=lm(Y~X1,data=data1)
summary(m1)
## 
## Call:
## lm(formula = Y ~ X1, data = data1)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -2.6440 -1.9128 -0.2151  2.2513  2.4075 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept) 19.01108    5.42272   3.506 0.009915 ** 
## X1           0.51797    0.06635   7.807 0.000106 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 2.174 on 7 degrees of freedom
## Multiple R-squared:  0.897,  Adjusted R-squared:  0.8823 
## F-statistic: 60.95 on 1 and 7 DF,  p-value: 0.0001065
# Pengujian Asumsi Model 1
# Uji Non-Heteroskedastisitas
# Breusch-Pagan Test
bptest(m1)
## 
##  studentized Breusch-Pagan test
## 
## data:  m1
## BP = 1.715, df = 1, p-value = 0.1903
# Glejser Test
e1=resid(m1)
ae1=abs(e1)
ae1
##         1         2         3         4         5         6         7         8 
## 1.9127561 1.9510242 2.4052142 2.4075419 0.2150838 2.2513035 1.1408752 0.7997207 
##         9 
## 2.6440410
aer1=lm(ae1~X1,data=data1)
summary(aer1)
## 
## Call:
## lm(formula = ae1 ~ X1, data = data1)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -1.3200 -0.4062  0.2952  0.5324  0.7722 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)
## (Intercept) -0.57193    2.04979  -0.279    0.788
## X1           0.02864    0.02508   1.142    0.291
## 
## Residual standard error: 0.8219 on 7 degrees of freedom
## Multiple R-squared:  0.157,  Adjusted R-squared:  0.03657 
## F-statistic: 1.304 on 1 and 7 DF,  p-value: 0.2911
# Uji Non-Autokorelasi
# Durbin-Watson Test
dwtest(m1, alternative='two.sided')
## 
##  Durbin-Watson test
## 
## data:  m1
## DW = 1.785, p-value = 0.5744
## alternative hypothesis: true autocorrelation is not 0
# Breusch-Godfrey Test
bgtest(m1)
## 
##  Breusch-Godfrey test for serial correlation of order up to 1
## 
## data:  m1
## LM test = 0.033549, df = 1, p-value = 0.8547
# Uji Normalitas Residual
shapiro.test(resid(m1))
## 
##  Shapiro-Wilk normality test
## 
## data:  resid(m1)
## W = 0.87986, p-value = 0.1565

# ---------------
# Model 2 RLS
# ---------------

m2=lm(Y~X2,data=data1)
summary(m2)
## 
## Call:
## lm(formula = Y ~ X2, data = data1)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -5.6496 -2.1172 -1.2392  0.9339  7.8929 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)   45.298      5.254   8.621 5.64e-05 ***
## X2             4.315      1.390   3.105   0.0172 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 4.394 on 7 degrees of freedom
## Multiple R-squared:  0.5793, Adjusted R-squared:  0.5192 
## F-statistic:  9.64 on 1 and 7 DF,  p-value: 0.0172
# Pengujian Asumsi Model 2
# Uji Non-Heteroskedastisitas
# Breusch-Pagan Test
bptest(m2)
## 
##  studentized Breusch-Pagan test
## 
## data:  m2
## BP = 0.072359, df = 1, p-value = 0.7879
# Glejser Test
e2=resid(m2)
ae2=abs(e2)
ae2
##         1         2         3         4         5         6         7         8 
## 0.3353100 1.7757020 3.0275565 2.1171842 5.6495807 1.2392084 0.9339012 4.6470912 
##         9 
## 7.8929294
aer2=lm(ae2~X2,data=data1)
summary(aer2)
## 
## Call:
## lm(formula = ae2 ~ X2, data = data1)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -2.3452 -1.7837 -0.6405  1.2837  4.7895 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)
## (Intercept)   1.4690     3.1460   0.467    0.655
## X2            0.4406     0.8321   0.529    0.613
## 
## Residual standard error: 2.631 on 7 degrees of freedom
## Multiple R-squared:  0.03851,    Adjusted R-squared:  -0.09885 
## F-statistic: 0.2804 on 1 and 7 DF,  p-value: 0.6128
# Uji Non-Autokorelasi
# Durbin-Watson Test
dwtest(m2, alternative='two.sided')
## 
##  Durbin-Watson test
## 
## data:  m2
## DW = 0.50193, p-value = 0.005426
## alternative hypothesis: true autocorrelation is not 0
# Breusch-Godfrey Test
bgtest(m2)
## 
##  Breusch-Godfrey test for serial correlation of order up to 1
## 
## data:  m2
## LM test = 5.4817, df = 1, p-value = 0.01922
# Uji Normalitas Residual
shapiro.test(resid(m2))
## 
##  Shapiro-Wilk normality test
## 
## data:  resid(m2)
## W = 0.93927, p-value = 0.5742

# ---------------
# Model 3 RLS
# ---------------

m3=lm(Y~X3,data=data1)
summary(m3)
## 
## Call:
## lm(formula = Y ~ X3, data = data1)
## 
## Residuals:
##    Min     1Q Median     3Q    Max 
## -4.693 -3.315 -2.592  3.937  9.297 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)
## (Intercept)  27.1873    18.9650   1.434    0.195
## X3            1.1399     0.6369   1.790    0.117
## 
## Residual standard error: 5.611 on 7 degrees of freedom
## Multiple R-squared:  0.314,  Adjusted R-squared:  0.216 
## F-statistic: 3.204 on 1 and 7 DF,  p-value: 0.1166
# Pengujian Asumsi Model 3
# Uji Non-Heteroskedastisitas
# Breusch-Pagan Test
bptest(m3)
## 
##  studentized Breusch-Pagan test
## 
## data:  m3
## BP = 0.62733, df = 1, p-value = 0.4283
# Glejser Test
e3=resid(m3)
ae3=abs(e3)
ae3
##        1        2        3        4        5        6        7        8 
## 3.314678 4.366959 2.592442 1.794065 4.692880 3.937164 3.246783 6.773392 
##        9 
## 9.297252
aer3=lm(ae3~X3,data=data1)
summary(aer3)
## 
## Call:
## lm(formula = ae3 ~ X3, data = data1)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -1.6039 -1.0955 -1.0751 -0.4915  4.5679 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)
## (Intercept)  13.4360     7.5924    1.77    0.120
## X3           -0.3034     0.2550   -1.19    0.273
## 
## Residual standard error: 2.246 on 7 degrees of freedom
## Multiple R-squared:  0.1682, Adjusted R-squared:  0.0494 
## F-statistic: 1.416 on 1 and 7 DF,  p-value: 0.2729
# Uji Non-Autokorelasi
# Durbin-Watson Test
dwtest(m3, alternative='two.sided')
## 
##  Durbin-Watson test
## 
## data:  m3
## DW = 1.117, p-value = 0.1651
## alternative hypothesis: true autocorrelation is not 0
# Breusch-Godfrey Test
bgtest(m3)
## 
##  Breusch-Godfrey test for serial correlation of order up to 1
## 
## data:  m3
## LM test = 0.80317, df = 1, p-value = 0.3701
# Uji Normalitas Residual
shapiro.test(resid(m3))
## 
##  Shapiro-Wilk normality test
## 
## data:  resid(m3)
## W = 0.81761, p-value = 0.03238

# ---------------
# Model 4 RLB
# ---------------

m4=lm(Y~X1+X2+X3,data=data1)
summary(m4)
## 
## Call:
## lm(formula = Y ~ X1 + X2 + X3, data = data1)
## 
## Residuals:
##       1       2       3       4       5       6       7       8       9 
## -0.2981 -0.2142  0.4714 -0.4746 -0.9524  0.4761  0.9274  0.7466 -0.6823 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept) 21.87353    4.07389   5.369  0.00302 ** 
## X1           0.41277    0.03067  13.460 4.05e-05 ***
## X2           2.20267    0.47199   4.667  0.00550 ** 
## X3          -0.07895    0.15551  -0.508  0.63330    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.8484 on 5 degrees of freedom
## Multiple R-squared:  0.9888, Adjusted R-squared:  0.9821 
## F-statistic: 147.1 on 3 and 5 DF,  p-value: 2.696e-05
#Pendeteksian Multikolinieritas
vif(m4)
##       X1       X2       X3 
## 1.403219 3.093549 2.607991
# Pengujian Asumsi Model 4
# Uji Non-Heteroskedastisitas
# Breusch-Pagan Test
bptest(m4)
## 
##  studentized Breusch-Pagan test
## 
## data:  m4
## BP = 0.52402, df = 3, p-value = 0.9136
# Glejser Test
e4=resid(m4)
ae4=abs(e4)
ae4
##         1         2         3         4         5         6         7         8 
## 0.2980857 0.2141744 0.4714083 0.4745650 0.9524106 0.4760829 0.9274363 0.7466056 
##         9 
## 0.6822975
aer4=lm(ae4~X1+X2+X3,data=data1)
summary(aer4)
## 
## Call:
## lm(formula = ae4 ~ X1 + X2 + X3, data = data1)
## 
## Residuals:
##        1        2        3        4        5        6        7        8 
## -0.24968 -0.37078 -0.06495 -0.01987  0.35744 -0.17650  0.37477  0.12608 
##        9 
##  0.02347 
## 
## Coefficients:
##              Estimate Std. Error t value Pr(>|t|)
## (Intercept)  1.000238   1.548904   0.646    0.547
## X1           0.002391   0.011660   0.205    0.846
## X2           0.035130   0.179452   0.196    0.853
## X3          -0.024936   0.059127  -0.422    0.691
## 
## Residual standard error: 0.3226 on 5 degrees of freedom
## Multiple R-squared:  0.04467,    Adjusted R-squared:  -0.5285 
## F-statistic: 0.07793 on 3 and 5 DF,  p-value: 0.9692
# Uji Non-Autokorelasi
# Durbin-Watson Test
dwtest(m4, alternative='two.sided')
## 
##  Durbin-Watson test
## 
## data:  m4
## DW = 1.6446, p-value = 0.233
## alternative hypothesis: true autocorrelation is not 0
# Breusch-Godfrey Test
bgtest(m4)
## 
##  Breusch-Godfrey test for serial correlation of order up to 1
## 
## data:  m4
## LM test = 0.51249, df = 1, p-value = 0.4741
# Uji Normalitas Residual
shapiro.test(resid(m4))
## 
##  Shapiro-Wilk normality test
## 
## data:  resid(m4)
## W = 0.93208, p-value = 0.5014