Ex 18. ๋ค์๊ณผ ๊ฐ์ ๋ฐ์ดํฐ ์ธํธ๊ฐ ์๋ค. ์ด ๋ฐ์ดํฐ ์ธํธ๋ฅผ Data Set 1์ด๋ผ๊ณ ํ์.
5 -2 6 14 -3 0 1 4 3 3 5
a. Data Set 1์ ํ๋ณธ ํ์คํธ์ฐจ๋ฅผ ๊ตฌํ๋ผ.
b. ์ด Data Set 1์ ๊ฐ ์์น์ 3์ ๋ํ์ฌ Data Set II๋ฅผ ์์ฑํ๋ผ. ๊ทธ๋ฆฌ๊ณ ์ด Data Set II์ ํ๋ณธ ํ์คํธ์ฐจ๋ฅผ ๊ตฌํ๋ผ.
c. Data Set I์ ๊ฐ ์์น์์ 6์ ๋บ ๊ฐ์ผ๋ก ๊ตฌ์ฑ๋ Data Set III๋ฅผ ์์ฑํ๋ผ. ๊ทธ๋ฆฌ๊ณ ์ด Data Set III์ ํ๋ณธ ํ์คํธ์ฐจ๋ฅผ ๊ตฌํ๋ผ.
Ex 19. 1,000 ๋ช ์ ํ์๋ค์ SAT์ GPS ์ฑ์ ์ ์๋กํ๊ณ ์๋ Data Set 1์ด ์ ์ฌ์ดํธ์ ์๋ก๋์ด ์๋ค.
a. SAT ์ฑ์ ์ ๋ฒ์์ ํ๋ณธ ํ์คํธ์ฐจ๋ฅผ ๊ตฌํ๋ผ.
b. GPS ์ฑ์ ์ ๋ฒ์์ ํ๋ณธ ํ์คํธ์ฐจ๋ฅผ ๊ตฌํ๋ผ.
[Solution]
install.packages("readxl")
library(readxl)
dataset1 <- read_excel("data1.xls")
str(dataset1)
# Data Set 1
sat <- dataset1[[1]]
gpa <- dataset1[[2]]
# list of Data Set
head(sat)
head(gpa)
# a.
range_SAT <- max(sat) - min(sat)
range_SAT
sd(sat)
# b.
range_GPA <- max(gpa) - min(gpa)
range_GPA
sd(gpa)
> str(dataset1)
> str(dataset1)
Classes โtbl_dfโ, โtblโ and 'data.frame': 1000 obs. of 2 variables:
$ SAT Score : num 1300 1520 1580 1430 1610 1230 1520 1320 1240 1480 ...
$ College GPA: num 3.66 2.92 2.66 2.27 2.35 2.02 2.94 1.76 2.35 3.16 ...
>
> # list of Data Set
> head(sat)
[1] 1300 1520 1580 1430 1610 1230
> head(gpa)
[1] 3.66 2.92 2.66 2.27 2.35 2.02
Ex 20. Data Set 1์ SAT์ฑ์ ์ ์ด์ฉํ์ฌ ๋ค์์ ๊ตฌํ๋ผ.
[Solution]
dataset1 <- read_excel("data1.xls")
str(dataset1)
# Population Data Set
sat <- dataset1[[1]]; head(sat)
# a.
range_SAT <- max(sat) - min(sat) ; range_SAT
sd(sat)
# Sample Data Set : First 25 Observations.
sat <- dataset1[[1]][1:25]; sat
# b.
range_SAT <- max(sat) - min(sat) ; range_SAT
sd(sat)
# Sample Data Set : First 25 Observations.
sat <- dataset1[[1]][26:50]; sat
# c.
range_SAT <- max(sat) - min(sat) ; range_SAT
sd(sat)
> # Population Data Set
> sat <- dataset1[[1]]; head(sat)
[1] 1300 1520 1580 1430 1610 1230
>
> # a.
> range_SAT <- max(sat) - min(sat) ; range_SAT
[1] 1350
> sd(sat)
[1] 212.5455
> # Sample Data Set : First 25 Observations.
> sat <- dataset1[[1]][1:25]; sat
[1] 1300 1520 1580 1430 1610 1230 1520 1320 1240 1480 1780 1870 1140 1580 1520 1510 1490 1760 1430 1630 1960 1330
[23] 1520 1430 1390
>
> # b.
> range_SAT <- max(sat) - min(sat) ; range_SAT
[1] 820
> sd(sat)
[1] 197.5373
> # Sample Data Set : Next 25 Observations.
> sat <- dataset1[[1]][26:50]; sat
[1] 1700 1320 1540 1510 1120 1690 1870 1450 1430 1850 1510 1510 1700 1330 1820 1360 1820 1670 1690 1330 1520 1180
[23] 1700 1430 1330
>
> # c.
> range_SAT <- max(sat) - min(sat) ; range_SAT
[1] 750
> sd(sat)
[1] 209.6052
Ex 21. Data Set 1์ GPA์ฑ์ ์ ์ด์ฉํ์ฌ ๋ค์์ ๊ตฌํ๋ผ.
[Solution]
dataset1 <- read_excel("data1.xls")
str(dataset1)
# Population Data Set
gpa <- dataset1[[2]]; head(gpa)
# a.
range_GPA <- max(gpa) - min(gpa) ; range_GPA
sd(gpa)
# Sample Data Set : First 25 Observations.
gpa <- dataset1[[2]][1:25]; gpa
# b.
range_GPA <- max(gpa) - min(gpa) ; range_GPA
sd(gpa)
# Sample Data Set : Next 25 Observations.
gpa <- dataset1[[2]][26:50]; gpa
# c.
range_GPA <- max(gpa) - min(gpa) ; range_GPA
sd(gpa)
> # Population Data Set
> gpa <- dataset1[[2]]; head(gpa)
[1] 3.66 2.92 2.66 2.27 2.35 2.02
>
> # a.
> range_GPA <- max(gpa) - min(gpa) ; range_GPA
[1] 4
> sd(gpa)
[1] 0.7407454