library(openxlsx)
library(ggplot2)
library(gridExtra)
sample1<-read.xlsx("http://kanggc.iptime.org/book/data/stat-1.xlsx") 
mid<-sample1$mid
final<-sample1$final
total<-sample1$total
grade<-sample1$grade
qp1<-qplot(x=1, y=mid, geom="boxplot")
qp2<-qplot(x=1, y=final, geom="boxplot")
qp3<-qplot(x=1, y=total, geom="boxplot")
marrangeGrob(grobs=list(qp1, qp2, qp3), nrow=1, ncol=3)
plot1<-ggplot(data=sample1, aes(x=1, y=mid)) + geom_boxplot() + ggtitle("Boxplot of Mid")+ theme(plot.title = element_text(hjust = 0.5))
plot2<-ggplot(data=sample1, aes(x=1, y=final)) + geom_boxplot() + ggtitle("Boxplot of Final")+ theme(plot.title = element_text(hjust = 0.5))
plot3<-ggplot(data=sample1, aes(x=1, y=total)) + geom_boxplot() + ggtitle("Boxplot of Total")+ theme(plot.title = element_text(hjust = 0.5))
marrangeGrob(grobs=list(plot1, plot2, plot3), nrow=1, ncol=3)