Simple fair coin toss code

cointoss.R

library(ggplot2)

### Imagine a coin is flipped 100 times
### You get 60 heads
### How can you assess if the coin is fair or not?

# Set up the plot
binom_density <- dbinom(0:100,100,.5)
flips <- data.frame(flip_count = 0:100, density = binom_density)

# Make the plot

ggplot(flips,aes(x = flip_count, y = density)) + geom_path() +
  theme_bw() + geom_rect(xmin = 60, xmax = 100, ymin = 0 ,ymax = .09, fill = 'red', alpha = .005)

# Get the probability of getting 60 or more heads in 100 flips given a fair coin
sum(dbinom(60:100,100,.5))