Exercise: Probability of Red, Green, and Black

  1. Calculate the probability of landing on green, red, and black.

  2. How can the RouletteSpin() function be used to compute or approximate these probabilities?

Exercise: Simulation Questions - Part 2

Now what happens if we:

  1. run the simulation again with the same number of trials?

  2. run the simulation with more trials, say 1 million?

Exercise: Conditions in R

We have touched on many of these before, but here are some examples of expressions (conditions) in R.

pi > 3 & pi < 3.5
c(1,3,5,7) %in% 1:3
1:3 %in% c(1,3,5,7)
rand.uniform <- runif(n = 1, min = 0, max = 1)
rand.uniform < .5

Exercise: Conditional Expression

Write a conditional statement that takes a playing card with two arguments:

Verify this works using the following inputs:

Exercise: Loops

Assume you plan to wager $1 on red for ten roulette spins. If the outcome is red you win a dollar and otherwise you lose a dollar. Write a loop that simulates ten rolls and determines your net profit or loss.

RouletteSpin <- function(num.spins){
  # function to simulate roulette spins
  # ARGS: number of spins
  # RETURNS: result of each spin
  outcomes <- data.frame(number = c('00','0',
                as.character(1:36)),
                color=c('green','green',
                rep(c('red','black'),18)))
  return(outcomes[sample(38,num.spins,replace=T),])
}
#hint: to get color from a single spin use
RouletteSpin(1)[2]
##    color
## 14 black