library(openxlsx)
library(dplyr)
library(ggplot2)
library(gridExtra)

df<-read.xlsx("http://kanggc.iptime.org/book/data/subtotal-e.xlsx")
df

dept_name_1 <- df %>% 
  group_by(dept, class) %>%
  summarise(mean_total = mean(total))
dept_name_1

dept_name_2 <- df %>% 
  group_by(dept, class) %>%
  summarise(sd_total = sd(total))
dept_name_2

plot1<-ggplot(data=dept_name_1, aes(x=dept, y=mean_total, fill=class)) +
  geom_col(position="dodge2") 
plot2<-ggplot(data=dept_name_2, aes(x=dept, y=sd_total, fill=class)) +
  geom_col(position="dodge2")
marrangeGrob(grobs=list(plot1, plot2), nrow=2, ncol=1)