facet_wrap add geom_hline

Minimal example using mtcars – you have to create a data frame with mean for each gear (in your case it’s Name). library(tidyverse) dMean <- mtcars %>% group_by(gear) %>% summarise(MN = mean(cyl)) ggplot(mtcars) + geom_point(aes(mpg, cyl)) + geom_hline(data = dMean, aes(yintercept = MN)) + facet_wrap(~ gear) For your case this should work: library(tidyverse) dMean <- … Read more