library(openxlsx)

sample1<-read.xlsx("http://kanggc.iptime.org/book/data/stat-1.xlsx", sheet=1, startRow=1, colNames = T) 

mid<-sample1$mid
final<-sample1$final
total<-sample1$total
grade<-sample1$grade

summary(sample1)

par(mfrow=c(1,3))
boxplot(mid, main="Box plot of mid")
boxplot(final, main="Box plot of final")
boxplot(total, main="Box plot of total")