1) The document describes how to perform t-tests and one-way ANOVA in R. It provides examples of using t.test() to compare the mean delivery times between two types and using aov() and TukeyHSD() to analyze differences in fuel efficiency between four treatments. 2) The t-test example finds a statistically significant difference (p=0.03) between the mean delivery times of type 1 (8.56 minutes) and type 2 (10.47 minutes). 3) The one-way ANOVA finds a statistically significant difference (p=0.007) between the mean fuel efficiencies of the four treatments. The TukeyHSD multiple comparisons test shows treatment 4 has

1. R 기초 – 평균차이검정,
일원배치분산분석
한림대학교 금융정보통계학과
이 윤 환

2. 평균차이 검정
t.test(
x,
y = NULL,
alternative = c("two.sided", "less", "greater"),
mu = 0,
paired = FALSE,
var.equal = FALSE,
conf.level = 0.95
)
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3. 평균차이 검정
> setwd("c://r_nur")
> delivery <- read.table("delivery.txt", header=TRUE)
> attach(delivery)
> t.test(time[type==2], time[type==1], var.equal=TRUE)
Welch Two Sample t-test
data: time[type == 2] and time[type == 1]
t = 2.3003, df = 24.777, p-value = 0.03013
alternative hypothesis: true difference in means is not equal to 0
95 percent confidence interval:
0.1999658 3.6358431
sample estimates:
mean of x mean of y
10.473529 8.555625
간호 통계 이윤환, yoonani72@gmail.com

4. 일원배치 분산분석
> one.way <- read.table("fuel.txt", header=T)
> attach(one.way)
> Trt <- factor(trt)
> one.way.anova <- aov(y ~ Trt)
> summary.aov(one.way.anova)
> model.tables(one.way.anova)
> Tukey <- TukeyHSD(one.way.anova)
> print(Tukey,3)
> plot(Tukey)
R을 활용한 통계적 개념, 방법, 응용 – 허명회 저 중
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5. 분산분석표
Df Sum Sq Mean Sq F value Pr(>F)
Trt 3 1636.5 545.5 5.4063 0.006876 **
Residuals 20 2018.0 100.9
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
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6. 다중 비교
Tukey multiple comparisons of means
95% family-wise confidence level
Fit: aov(formula = y ~ Trt)
$Trt
diff lwr upr p adj
2-1 13 -3.23 29.23 0.146
3-1 4 -12.23 20.23 0.900
4-1 -10 -26.23 6.23 0.338
3-2 -9 -25.23 7.23 0.427
4-2 -23 -39.23 -6.77 0.004
4-3 -14 -30.23 2.23 0.107
간호 통계 이윤환, yoonani72@gmail.com

7. 다중비교
간호 통계 이윤환, yoonani72@gmail.com