Laporan Praktikum 2

Visualisasi Data

Plot

# Dasar Plot
x <- 1:40
y <- rnorm(40,5,1)

plot(x,y,type="p")

plot(x,y,type="o")

plot(x,y,type="n")

plot(x,y,type="p",xlab="Sumbu x",ylab="Sumbu y",
main="Bilangan Acak Normal",col=2,pch=16)

plot(x,y,type="p",xlab="Sumbu x",ylab="Sumbu y",
main="Bilangan Acak Normal",col=rainbow(40),
pch=16,cex=2,xlim=c(0,50),ylim=c(2.5,7.5))

# Menambahkan amatan
x1 <- 41:50
y1 <- rnorm(10,5,1)
points(x1,y1,cex=2)

# Menambahkan garis
x2 <- rep(40.5,20)
y2 <- seq(min(c(y,y1)),max(c(y,y1)),length=20)
lines(x2,y2,col=4,lwd=2,lty=2)
abline(h=mean(y),col="red",lwd=2.5)
abline(a=2,b=1/10,col="maroon3",lwd=2,lty=2)

# Menambahkan tanda panah
arrows(x0=30,y0=3.5,x1=40,y1=mean(y)-.1,lwd=2)

# Menambahkan tulisan
text(x=29,y=3.3,labels="Titik potong",cex=0.7)
text(x=3,y=7.3,labels="Data awal",cex=0.7)
text(x=46,y=7.3,labels="Data baru",cex=0.7)

Latihan 1

Could you explain what are these programs do for?

plot(sin,-pi,2*pi)

plot(table(rpois(100,5)),type="h",col="red",
lwd=1,main="rpois(100,lambda=5)")

1. Membuat plot nilai sin dari -pi sampai 2*pi 2. Membuat plot sebaran poisson dengan tipe garis vertikal dari sumbu x ke titik. jumlah amatan sebanyak 100 dan parameter lambda 5

Latihan 2

Create some programs to make the graph below

a1 <- 1:25
a2 <- rnorm(25,4,2)
plot(a1,a2,pch="w",main="W")

Latihan 3

plot(a1,a2,type="n",main="W")
text(a1,a2,labels=paste("w",1:25,sep=""),col=rainbow(25),cex=0.8)

Latihan 4

Create some programs to make the graph below, using 100 observation of 𝑋~𝜒2 (4)

x <- rchisq(100,df=4)
hist(x,freq=FALSE,ylim=c(0,0.2))
curve(dchisq(x,df=4),col=2,lty=2,lwd=2,add=TRUE)

Format 2,2

par(mfrow=c(2,2))
plot(1:40,y,type="p",xlab="Sumbu x",ylab="Sumbu y",
main="Bilangan Acak Normal",col=2,pch=16)
plot(sin,-pi, 2*pi)
plot(table(rpois(100,5)),type="h",col="red",
lwd=1,main="rpois(100,lambda=5)")
plot(a1,a2,type="n",main="W")
text(a1,a2,labels=paste("w",1:25,sep=""),
col=rainbow(25),cex=0.8)

par(mfcol=c(2,2))
plot(1:40,y,type="p",xlab="Sumbu x",ylab="Sumbu y",
main="Bilangan Acak Normal",col=2,pch=16)
plot(sin,-pi, 2*pi)
plot(table(rpois(100,5)),type="h",col="red",lwd=1,
main="rpois(100,lambda=5)")
plot(a1,a2,type="n",main="W")
text(a1,a2,labels=paste("w",1:25,sep=""),
col=rainbow(25),cex=0.8)

Latihan 5

Create 4 graph in one window from 100 random numbers which follow N(5,1), with format described bellow

windows()
yb <- rnorm(100,5,1)
split.screen(c(2,2))
## [1] 1 2 3 4
screen(3)
boxplot(yb)
title("Boxplot Bilangan Acak Normal",cex.main=0.7)
screen(4)
xb <- 1:100
plot(xb,yb,type="l",lwd=2,col="blue")
title("Line Plot Bilangan Acak Normal",cex.main=0.7)
screen(2)
hist(yb,freq=FALSE,main=NULL,ylim=c(0,0.5))
x <- yb
curve(dnorm(x,5,1),col="red",lty=2,lwd=2,add=TRUE)
title("Histogram Bilangan Acak Normal",cex.main=0.7)
screen(1)
plot(xb,yb,pch=16,col=rainbow(100))
title("Scatter Plot Bilangan Acak Normal",cex.main=0.7)

Pembangkitan Bilangan Acak

Pembangkitan Bilangan Acak

#pembangkitan bilangan acak
x <- rnorm(10) #x~N(0,1)
x1 <- rnorm(10,3,2) #x1~N(3,sd=2)
x2 <- rbinom(10,1,0.4) #x2~bernoulli(0.4)

#mencari nilai peluang kumulatif peubah acak
p1 <- pnorm(1.645) #P(Z<1.645)=0.95
p2 <- pnorm(1.96) #P(Z<1.975)=0.975
p3 <- pnorm(-1.96)
p4 <- pf(15,df1=10,df2=15)

#mencari nilai kuantil dari peluang peubah acak
q1 <- qnorm(0.975)
q2 <- qnorm(0.95,2,1) #X~N(2,1), P(X<x)=0.95

#mencari nilai density peubah acak
##plot density normal
a <- seq(-4,4,length=1000)
da <- dnorm(a)
plot(a,da)

Latihan 1

Membangkitkan bilangan acak eksponensial

#Eksponensial(lambda=6)
eks <- function(n,lambda){
U <- runif(n)
X <- -log(1-U)/lambda
return(X)
}
yy1 <- eks(1000,6) #inverse transform method
yy2 <- rexp(1000,rate=6) #fungsi bawaan R
par(mfrow=c(1,2))
hist(yy1,main="Exp dari Inverse Transform")
hist(yy2,main="Exp dari fungsi rexp")

Latihan 2

Bangkitkan bilangan acak yang memiliki fkp 𝑓𝑌 𝑦 =3𝑦 2; 0 < 𝑦 < 1 menggunakan acceptance-rejection method!

ar <- function(n,x0,x1,f) {
xx <- seq(x0,x1,length=10000)
c <- max(f(xx))
terima <- 0; iterasi <- 0
hasil <- numeric(n)
while(terima<n) {
x <- runif(1,x0,x1)
y1<- runif(1,0,c)
y2<- f(x)
if(y1<=y2) {
terima <- terima+1
hasil[terima]<-x }
iterasi <- iterasi+1 }
list(hasil=hasil,iterasi=iterasi)
}
set.seed(10)
f <- function(x) {3*x^2}
yyy <- ar(100,0,1,f)

yyy
## $hasil
##   [1] 0.8647212 0.7751099 0.8382877 0.7707715 0.5355970 0.8613824 0.2036477
##   [8] 0.7979930 0.7438394 0.3443435 0.9837322 0.6935082 0.6331153 0.8880315
##  [15] 0.7690405 0.6483695 0.8795432 0.9360689 0.7233519 0.7620444 0.9868082
##  [22] 0.8760261 0.7240640 0.8140516 0.5588949 0.8900940 0.7456896 0.8480646
##  [29] 0.8703302 0.8223331 0.8508123 0.7709219 0.8953595 0.5803863 0.5982260
##  [36] 0.9235285 0.7367755 0.6898170 0.8301572 0.9293209 0.9095163 0.5347576
##  [43] 0.3478601 0.8759762 0.7286815 0.8749293 0.6988356 0.8312562 0.5572238
##  [50] 0.6647687 0.7400502 0.9806898 0.3800746 0.7553169 0.5184889 0.8879149
##  [57] 0.9177773 0.8084086 0.8537441 0.4232184 0.7604306 0.3405763 0.3886568
##  [64] 0.4774175 0.5387605 0.9485434 0.7124685 0.9081691 0.9457656 0.7716899
##  [71] 0.6946655 0.5368832 0.8481593 0.8242752 0.5123742 0.3152032 0.9924487
##  [78] 0.9327120 0.9892809 0.6283590 0.5254605 0.8810815 0.5291748 0.5765517
##  [85] 0.7231807 0.8761180 0.3995670 0.8986123 0.9335217 0.7859216 0.7784128
##  [92] 0.6955333 0.9060413 0.9916424 0.4729846 0.9770567 0.9386110 0.9959093
##  [99] 0.8543663 0.8309547
## 
## $iterasi
## [1] 322
par(mfrow=c(1,1))
hist(yyy$hasil,
main="f(x)=3*x^2", prob=T)
x <- seq(0, 1, 0.01)
lines(x, f(x), lwd=2, col=4)

Pembangkitan bilangan acak untuk model analisis regresi

set.seed(123)
X1 <- runif(25,10,25)
X2 <- runif(25,90,200)
Y <- 10 + 2.3*X1 + 0.7*X2 + rnorm(25,0,9)
model1 <- lm(Y~X1)
summary(model1)
## 
## Call:
## lm(formula = Y ~ X1)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -29.991 -17.738  -2.632  17.896  33.171 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  131.846     19.741   6.679 8.18e-07 ***
## X1             1.049      1.015   1.033    0.312    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 22.42 on 23 degrees of freedom
## Multiple R-squared:  0.04433,    Adjusted R-squared:  0.002775 
## F-statistic: 1.067 on 1 and 23 DF,  p-value: 0.3124
model2 <- lm(Y~X2)
summary(model2)
## 
## Call:
## lm(formula = Y ~ X2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -31.804  -4.850  -1.606  10.011  20.569 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept) 70.83913   13.86879   5.108 3.57e-05 ***
## X2           0.58213    0.09767   5.960 4.46e-06 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 14.38 on 23 degrees of freedom
## Multiple R-squared:  0.607,  Adjusted R-squared:  0.5899 
## F-statistic: 35.52 on 1 and 23 DF,  p-value: 4.464e-06
model3 <- lm(Y~X1+X2)
summary(model3)
## 
## Call:
## lm(formula = Y ~ X1 + X2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -14.8291  -4.5994  -0.4576   5.0602  20.5307 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept) -0.62881   13.40229  -0.047    0.963    
## X1           2.72951    0.40701   6.706 9.67e-07 ***
## X2           0.72459    0.06105  11.869 4.91e-11 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 8.427 on 22 degrees of freedom
## Multiple R-squared:  0.8709, Adjusted R-squared:  0.8592 
## F-statistic: 74.21 on 2 and 22 DF,  p-value: 1.66e-10
model4 <- lm(Y~X1:X2)
summary(model4)
## 
## Call:
## lm(formula = Y ~ X1:X2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -20.929  -7.009  -1.430   2.856  37.374 
## 
## Coefficients:
##              Estimate Std. Error t value Pr(>|t|)    
## (Intercept) 80.645221  10.481428   7.694 8.32e-08 ***
## X1:X2        0.027491   0.003929   6.997 3.94e-07 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 12.97 on 23 degrees of freedom
## Multiple R-squared:  0.6804, Adjusted R-squared:  0.6665 
## F-statistic: 48.96 on 1 and 23 DF,  p-value: 3.942e-07
model5 <- lm(Y~X1*X2)
summary(model5)
## 
## Call:
## lm(formula = Y ~ X1 * X2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -14.4425  -4.5808  -0.6702   4.6431  20.2409 
## 
## Coefficients:
##              Estimate Std. Error t value Pr(>|t|)  
## (Intercept) 11.625896  37.941991   0.306   0.7623  
## X1           2.063573   1.967526   1.049   0.3062  
## X2           0.635870   0.263687   2.411   0.0251 *
## X1:X2        0.004905   0.014165   0.346   0.7326  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 8.6 on 21 degrees of freedom
## Multiple R-squared:  0.8716, Adjusted R-squared:  0.8533 
## F-statistic: 47.53 on 3 and 21 DF,  p-value: 1.548e-09
R2 <- matrix(c(summary(model1)$r.squared,
summary(model1)$adj.r.squared,
summary(model2)$r.squared,
summary(model2)$adj.r.squared,
summary(model3)$r.squared,
summary(model3)$adj.r.squared,
summary(model4)$r.squared,
summary(model4)$adj.r.squared,
summary(model5)$r.squared,
summary(model5)$adj.r.squared), 5, byrow=T)
colnames(R2)<-c("R2","R2.adj"); R2*100
##             R2     R2.adj
## [1,]  4.432592  0.2774876
## [2,] 60.699195 58.9904640
## [3,] 87.090357 85.9167529
## [4,] 68.036265 66.6465370
## [5,] 87.163648 85.3298839
coef(model3)
## (Intercept)          X1          X2 
##  -0.6288095   2.7295126   0.7245911
confint(model3)
##                   2.5 %     97.5 %
## (Intercept) -28.4234482 27.1658292
## X1            1.8854322  3.5735929
## X2            0.5979779  0.8512044
cbind(coef(model3), confint(model3))
##                              2.5 %     97.5 %
## (Intercept) -0.6288095 -28.4234482 27.1658292
## X1           2.7295126   1.8854322  3.5735929
## X2           0.7245911   0.5979779  0.8512044
anova(model3)
## Analysis of Variance Table
## 
## Response: Y
##           Df  Sum Sq Mean Sq  F value    Pr(>F)    
## X1         1   536.4   536.4   7.5538   0.01173 *  
## X2         1 10002.4 10002.4 140.8614 4.911e-11 ***
## Residuals 22  1562.2    71.0                       
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
par(mfrow=c(2,2)); plot(model3)