facet_wrap add geom_hline

Question

I have the following code for my ggplot - the facet_wrap function draws out 20 plots on the page for each Name and there are 5 Pcode along the x-axis. I would like to calcul

Answer 1

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 <- UKWinners %>%
    group_by(Name) %>%
    summarise(MN = mean(TE.Contr.))
ggplot(UKWinners) +
    geom_point(aes(Pcode, TE.Contr.)) +
    geom_hline(data = dMean, aes(yintercept = MN)) +
    facet_wrap(~ Name)