I am trying to make a bar chart with two grouping variables, only one of the grouping variables act as the predictor on a continuous y. I would like to put info of the two grouping variables within a single bar chart. Could you teach me how to do that please?
Using the mtcars dataset in R, I can do it in the following way,
a=tapply(mtcars$mpg,list(mtcars$vs,mtcars$gear),mean) a x1=as.factor(c(rep(0,3),rep(1,3))) x2=as.factor(c(rep(c(3:5),2))) mean=c(a[1,],a[2,]) dat=data.frame(x1,x2,mean) ggplot(dat,aes(x=x1,y=mean,fill=x2))+geom_bar(stat='identity',position='dodge')
but instead of manually compute means before plotting, I would like to use stat_summary() to do the computing for me with the raw data. I tried the following code, didnt work:
Please give me some advice. Thank you very much.