USING R IN INTRODUCTION STATISTICS

1. USING R IN INTRODUCTION STATISTICS
Yayan.m@gmail.com
DATASET
Kelas f
Nilai Tengah
(xi)
a b c
10-19 9 15
20-29 20 25
30-39 26 35
40-49 35 45
50-59 22 55
60-69 17 65
70-79 11 75
80-89 6 85
90'99 4 95
# Load data from file excel
> library(readxl)
> DATASETCOVAR <- read_excel("D:/R/DATASETCOVAR.xlsx")
> View(DATASETCOVAR)
> dataset.1 <- DATASETCOVAR[,c(2,3)]
> dataset.1
# A tibble: 9 × 2
f `Nilai Tengah (xi)`
<dbl> <dbl>
1 9 15
2 20 25
3 26 35
4 35 45
5 22 55
6 17 65
7 11 75
8 6 85
9 4 95
# Karena data diatas dalam bentuk table maka kita perlu rubah kedalam bent
uk vector, sebagai contoh
F xi
1 2 1
2 1 3
3 1 2
Menjadi [1]1 1 3 2
> rep(DATASETCOVAR$`Nilai Tengah (xi)`,DATASETCOVAR$f)
# Maka mean/nilai tengah akan didapat
> mean(rep(DATASETCOVAR$`Nilai Tengah (xi)`,DATASETCOVAR$f))
[1] 47.66667
# kemudian kita akan cari |xi-xrata|

2. > abs(DATASETCOVAR$`Nilai Tengah (xi)`- mean(rep(DATASETCOVAR$`Nilai Tenga
h (xi)`,DATASETCOVAR$f)))
[1] 32.666667 22.666667 12.666667 2.666667 7.333333 17.333333 27.333333
37.333333 47.333333
# kemudian kita akan cari |xi-xrata|^2
> (abs(DATASETCOVAR$`Nilai Tengah (xi)`- mean(rep(DATASETCOVAR$`Nilai Teng
ah (xi)`,DATASETCOVAR$f))))^2
[1] 1067.111111 513.777778 160.444444 7.111111 53.777778 300.44444
4 747.111111
[8] 1393.777778 2240.444444
# kemudian kita akan cari |xi-xrata|^2 * f
> (abs(DATASETCOVAR$`Nilai Tengah (xi)`- mean(rep(DATASETCOVAR$`Nilai Teng
ah (xi)`,DATASETCOVAR$f))))^2*DATASETCOVAR$f
[1] 9604.0000 10275.5556 4171.5556 248.8889 1183.1111 5107.5556 821
8.2222 8362.6667
[9] 8961.7778
#Maka Ragam atau variance, dan Standar deviasi atau simpangan bakunya dida
pat
> sum((abs(DATASETCOVAR$`Nilai Tengah (xi)`- mean(rep(DATASETCOVAR$`Nilai
Tengah (xi)`,DATASETCOVAR$f))))^2*DATASETCOVAR$f)
[1] 56133.33
> b <- sum((abs(DATASETCOVAR$`Nilai Tengah (xi)`- mean(rep(DATASETCOVAR$`N
ilai Tengah (xi)`,DATASETCOVAR$f))))^2*DATASETCOVAR$f)
> a <- sum(DATASETCOVAR$f)
> a
[1] 150
# Ragam atau Variance
> b/a
[1] 374.2222
# Simpangan baku atau standard deviasi
> sqrt(b/a)
[1] 19.34482