Permutation hypothesis test

infer_permutation_test.R

library(tidyverse)
library(infer)

africa_results <-
  "https://rudeboybert.github.io/SDS220/static/PS/africa_results.csv" %>%
  read_csv() %>%
  select(priming_number, how_many_countries)
View(africa_results)

# What actually happened! Observed difference
obs_diff <- africa_results %>%
  specify(formula = how_many_countries ~ priming_number) %>%
  calculate(stat = "diff in means",
            order = c("Primed with 14 countries", "Primed with 94 countries"))
obs_diff

# Shuffle!
africa_results %>%
  specify(formula = how_many_countries ~ priming_number) %>%
  hypothesize(null = "independence") %>%
  generate(reps = 1)

# Build null distribution
null_distribution <- africa_results %>%
  specify(formula = how_many_countries ~ priming_number) %>%
  hypothesize(null = "independence") %>%
  generate(reps = 1000) %>%
  calculate(stat = "diff in means", order = c("Primed with 14 countries", "Primed with 94 countries"))

# Plot!
ggplot(null_distribution, aes(x=stat)) +
  geom_histogram()

null_distribution %>%
  visualize(obs_stat = obs_diff, direction = "both")