library(ggplot2)
library(zoo)
## 
## Attaching package: 'zoo'
## The following objects are masked from 'package:base':
## 
##     as.Date, as.Date.numeric
library(car)
## Loading required package: carData
library(stats)
# Input Data
data <- data.frame(
Y = c(57.5, 52.8, 61.3, 67.0, 53.5, 62.7, 56.2, 68.5,69.2),
X1 = c(78, 69, 77, 88, 67, 80, 74, 94, 102),
X2 = c(2.75, 2.15, 4.41, 5.52, 3.21, 4.32, 2.31, 4.3,3.71),
X3 = c(29.5, 26.3, 32.2, 36.5, 27.2, 27.7, 28.3, 30.3, 28.7)
)
data
##      Y  X1   X2   X3
## 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 67.0  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 4.30 30.3
## 9 69.2 102 3.71 28.7
# a. Scatter Umur dan panjang bayi
ggplot(data, aes(x = X1, y = Y)) +
  geom_point(color = "deeppink4", size = 3) +
  geom_smooth(method = "lm", se = FALSE,
              color =  "ivory4", linetype = "twodash") +
  labs(
    title = "Scatter Plot umur bayi VS panjang bayi",
    x = "Umur", y = "Panjang bayi"
  ) +
  scale_x_continuous(breaks = seq(65, 105, 2)) +
  scale_y_continuous(breaks = seq(52, 72, 1)) +
  theme_minimal()
## `geom_smooth()` using formula = 'y ~ x'

# b. Scatter Berat badan bayi dan Panjang bayi 
ggplot(data, aes(x = X2, y = Y)) +
geom_point(color =  "#9AC0CD", size = 3) +
geom_smooth(method = "lm", se = FALSE,
              color = "#EEE0E5", linetype = "twodash") +
labs(
    title = "Scatter Plot berat badan bayi VS Panjang bayi",
    x = "Berat Badan", y = "Panjang Bayi"
  ) +
  scale_x_continuous(breaks = seq(2, 6, 0.5)) +
  scale_y_continuous(breaks = seq(52, 72, 1)) +
  theme_minimal()
## `geom_smooth()` using formula = 'y ~ x'

# c. Scatter X3 dan Y
ggplot(data, aes(x = X3, y = Y)) +
geom_point(color = "yellow", size = 3) +
  geom_smooth(method = "lm", se = FALSE,
              color = "hotpink3", linetype = "twodash") +
  labs(
    title = "Scatter Plot lingkar dada bayi VS Panjang bayi",
    x = "lingkar dada bayi", y = "panjang bayi"
  ) +
  scale_x_continuous(breaks = seq(25, 40, 1)) +
  scale_y_continuous(breaks = seq(52, 72, 1)) +
theme_minimal()
## `geom_smooth()` using formula = 'y ~ x'

#---Regresi Linear Berganda---#
#Model Variabel Y dan X1 X2 X3
RLB=lm(Y~X1+X2+X3,data=data)
summary(RLB)
## 
## Call:
## lm(formula = Y ~ X1 + X2 + X3, data = data)
## 
## 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
#Uji Multikolinieritas
vif(RLB)
##       X1       X2       X3 
## 1.403219 3.093549 2.607991
##Uji Non-Heteroskedastisitas
#1.Uji breusch-pagan
library(lmtest)
bptest(RLB)
## 
##  studentized Breusch-Pagan test
## 
## data:  RLB
## BP = 0.52402, df = 3, p-value = 0.9136
#2.Uji gletser
#Membuat absolute residual
data$abs_residual <- abs(residuals(RLB))
data$abs_residual
## [1] 0.2980857 0.2141744 0.4714083 0.4745650 0.9524106 0.4760829 0.9274363
## [8] 0.7466056 0.6822975
glejser <- lm(abs_residual ~ X1 + X2 + X3, data = data) 
summary(glejser)
## 
## Call:
## lm(formula = abs_residual ~ X1 + X2 + X3, data = data)
## 
## 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
#1.Uji breusch-godfrey
bgtest(RLB)
## 
##  Breusch-Godfrey test for serial correlation of order up to 1
## 
## data:  RLB
## LM test = 0.51249, df = 1, p-value = 0.4741
#2.Uji durbin-watson
dwtest(RLB, alternative='two.sided')
## 
##  Durbin-Watson test
## 
## data:  RLB
## DW = 1.6446, p-value = 0.233
## alternative hypothesis: true autocorrelation is not 0
#Uji Normalitas
##Uji shapiro-wilk
shapiro.test(residuals(RLB))
## 
##  Shapiro-Wilk normality test
## 
## data:  residuals(RLB)
## W = 0.93208, p-value = 0.5014

```