frequency polygon

R code of the ggplot2 example

library(ggplot2)
library(dplyr)
library(HistData)

children <- GaltonFamilies |>
  mutate(child = factor(gender, levels = c("female", "male"), labels = c("Daughters", "Sons")))

## Each name goes above the peak of its polygon, in the same 1-inch bins.
peaks <- children |>
  count(child, height = round(childHeight)) |>
  group_by(child) |>
  slice_max(n, n = 1, with_ties = FALSE)

p <- ggplot(children, aes(x = childHeight, colour = child)) +
  geom_freqpoly(binwidth = 1, center = 0, linewidth = 0.7) +
  geom_text(data = peaks, aes(x = height, y = n, label = child), vjust = -0.7, size = 3.5) +
  scale_x_continuous(labels = lex_number, breaks = lex_break_breaks, expand = lex_break_expand) +
  scale_y_continuous(labels = lex_number, expand = expansion(mult = c(0, 0.15))) +
  labs(title = "Sons measured about 5 inches more than daughters",
       subtitle = "Adult height of 934 children of 205 families, in 1-inch bins",
       x = "Height (inches)", y = "Children",
       caption = "Data: Galton 1886, via the HistData R package") +
  theme_lex_viz(break_not_zero = "x") +
  theme(legend.position = "none")