Мой предыдущий ответ не прошел весь путь. Вот повтор. Пример из ответа @ eyjo.
students <- 400
schools <- 5
df <- data.frame(
id = 1:students,
school = sample(paste("school", 1:schools, sep = ""), size = students, replace = TRUE),
results = sample(c("passed", "failed"), size = students, replace = TRUE, prob = c(.8, .2)))
r <- aggregate(results ~ school, FUN = table, data = df)
r <- do.call(cbind, r) # "flatten" the result
r <- as.data.frame(cbind(r, sum = rowSums(r)))
r$perc.passed <- round(with(r, (passed/sum) * 100), 0)
library(ggplot2)
ggplot(r, aes(x = school, y = perc.passed)) +
theme_bw() +
geom_bar(stat = "identity")