install.packages("dplyr")
install.packages("readxl")
install.packages("ggplot2")

library(readxl)
library(ggplot2)
#write your folder name here
Dominos <- read_excel("~/YourFolderName/Dominos.xlsx")
View(Dominos)

mean(Dominos$Time)

# Perform the one-tailed t test.
t.test(Dominos$Time, alternative = "less", mu=173.62)