Compare the mean of multiple variables within two groups

#Sample data
set.seed(42)
DB = data.frame(Group =c(rep("1",16),
                         rep("2",4)) , 
                Score1 = sample(1:20,20, replace = T),
                Score2 = sample(1:20,20, replace = T),
                Score3 = sample(1:20,20, replace = T),
                Score4 = sample(1:20,20, replace = T))

I want to plot two bar charts comparing the mean of each score in both groups. So the right side will be with a Title "Group 1 mean scores" and left side (left barchart) is "Group 2 mean scores" Thanks.

CodePudding user response：

You can pivot to long format and use stat = "summary"

library(tidyverse)

DB %>%
  pivot_longer(-1, names_to = "Score") %>%
  ggplot(aes(Group, value, fill = Score))  
  geom_bar(position = position_dodge(width = 0.8, preserve = "total"), 
           stat = "summary", fun = mean, width = 0.6)  
  scale_fill_brewer(palette = "Set2")  
  theme_minimal(base_size = 20)

Or if you prefer facets, you can do:

library(tidyverse)

DB %>%
  pivot_longer(-1, names_to = "Score") %>%
  mutate(Group = paste("Group", Group)) %>%
  ggplot(aes(Score, value, fill = Score))  
  geom_bar(stat = "summary", fun = mean, width = 0.6)  
  scale_fill_brewer(palette = "Set2", guide = "none")  
  facet_grid(.~Group)  
  theme_bw(base_size = 20)

^{Created on 2022-11-13 with reprex v2.0.2}