twins

Description

A data frame containing data collected in the mid 20th century by Cyril Burt from a study tracked down identical twins who were separated at birth: one child was raised in the home of their biological parents and the other in a foster home. In an attempt to answer the question of whether intelligence is the result of nature or nurture, both children were given IQ tests.

Usage

twins

Format

A data frame with 27 observations on the following 2 variables.

foster

IQ score of the twin raised by Foster parents.

biological

IQ score of the twin raised by Biological parents.

Examples

library(ggplot2)
library(dplyr)
library(tidyr)

plot_data <- twins |>
  pivot_longer(cols = c(foster, biological), names_to = "twin", values_to = "iq")

ggplot(plot_data, aes(iq, fill = twin)) +
  geom_histogram(color = "white", binwidth = 5) +
  facet_wrap(~twin) +
  theme_minimal() +
  labs(
    title = "IQ of identical twins",
    subtitle = "Separated at birth",
    x = "IQ",
    y = "Count",
    fill = ""
  )