如何在数据帧和 ggplot2 中添加错误栏？

Question

I am making a grouped bar graph using ggplot2. However, I am having trouble adding sd/sem. The standard errors are: '1,2,3,1'. How can I add Error Bar to this bar graph?

survey <- data.frame(group=rep(c("LG", "RM"),each=2),
                sample=rep(c("sample1", "sample2"),1),
                values=c(200,50,300,25 ))


library(ggplot2)
ggplot(survey, aes(x=sample, y=values, fill=group)) + 
 geom_bar(stat="identity", position=position_dodge())

Answer 1

In this case just put the fixed values directly, as they were calculated already somewhere else.

survey <- data.frame(group=rep(c("LG", "RM"),each=2),
                     sample=rep(c("sample1", "sample2"),1),
                     values=c(200,50,300,25 ),
                     se=c(1,2,3,1)) #added values here


library(ggplot2)
ggplot(survey, aes(x=sample, y=values, fill=group)) + 
  geom_bar(stat="identity", position=position_dodge())+
  geom_errorbar(aes(ymin=values - se, ymax=values + se),
                position=position_dodge(width = 0.9),width=0.5)

gives: