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

total
grade

counts<-table(total, grade)
barplot(counts, main="Bar Chart of Total Score", xlab="Grade")