data(sleep)
str(sleep)
## 'data.frame': 20 obs. of 3 variables:
## $ extra: num 0.7 -1.6 -0.2 -1.2 -0.1 3.4 3.7 0.8 0 2 ...
## $ group: Factor w/ 2 levels "1","2": 1 1 1 1 1 1 1 1 1 1 ...
## $ ID : Factor w/ 10 levels "1","2","3","4",..: 1 2 3 4 5 6 7 8 9 10 ...
summary(sleep)
## extra group ID
## Min. :-1.600 1:10 1 :2
## 1st Qu.:-0.025 2:10 2 :2
## Median : 0.950 3 :2
## Mean : 1.540 4 :2
## 3rd Qu.: 3.400 5 :2
## Max. : 5.500 6 :2
## (Other):8
#comparing paried samples
library(rstatix)
##
## Attaching package: 'rstatix'
## The following object is masked from 'package:stats':
##
## filter
library(stringr)
sleep <- sleep %>%
mutate(group = factor(group, labels = c("A", "B")))
A_group <- sleep %>%
filter(group == "A") %>%
select(extra)
B_group <- sleep %>%
filter(group == "B") %>%
select(extra)
t_test_A_and_B_group1 <- t.test(A_group$extra, B_group$extra, var.equal = TRUE)
t_test_A_and_B_group1
##
## Two Sample t-test
##
## data: A_group$extra and B_group$extra
## t = -1.8608, df = 18, p-value = 0.07919
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
## -3.363874 0.203874
## sample estimates:
## mean of x mean of y
## 0.75 2.33
#The result shows that there is statiscially no difference between group A and group B