Simulating a coin flip in R

use the sample() function to sample from a vector of ones (heads) and zeros (tails).

?sample

sample.space <- c(0,1)
theta <- 0.5 # this is a fair coin
N <- 20 # we want to flip a coin 20 times

flips <- sample(sample.space, 
                size = N, 
                replace = TRUE, 
                prob = c(theta, 1 - theta))

flips

 [1] 0 0 1 1 1 1 0 0 0 1 0 0 1 0 0 1 0 0 1 1

use the function rbinom() to draw a number from a Bernoulli distribution:

?rbinom

theta <- 0.5 # this is a fair coin
N <- 20

flips <- rbinom(n = N, 
                size = 1, 
                prob = theta)

flips

 [1] 0 1 0 0 1 0 0 1 1 1 0 1 0 0 1 1 1 1 1 0

use the function rbinom() to draw numbers from a binomial distribution:

theta <- 0.5 # this is a fair coin
N <- 20

flips <- rbinom(n = 1, 
                size = N, 
                prob = theta)

flips

[1] 10