# SOCR EduMaterials Activities Poisson Distribution

(diff) ← Older revision | Current revision (diff) | Newer revision → (diff)

## This is an activity to explore the Poisson Probability Distribution.

• Exercise 1: Use SOCR to graph and print the distribution of a Poisson random variable with λ = 2. What is the shape of this distribution?
• Exercise 2: Use SOCR to graph and print the distribution of a Poisson random variable with λ = 15. What is the shape of this distribution? What happens when you keep increasing λ?
• Exercise 3: Let $X \sim Poisson(5)$. Find $P(3 \le X < 10)$, and $P(X >10 | X \ge 4)$.
• Exercise 4: Poisson approximation to binomial: Graph and print $X \sim b(60, 0.02)$. Approximate this probability distribution using Poisson. Choose three values of X and compute the probability for each one using Poisson and then using binomial. How good is the approximation?

Below you can see the distribution of a Poisson random variable with λ = 5. In this graph you can also see the probability that between 2 and 5 events will occur.

• Exercise 5: People enter a gambling casino at a rate of 1 for every two minutes.
• What is the probability that no one enters between 12:00 and 12:05?
• What is the probability that at least 4 people enter the casino during that time?
• Exercise 6: Let X1 denote the number of vehicles passing a particular point on the eastbound lane of a highway in 1 hour. Suppose that the Poisson distribution with mean λ1 = 5 is a reasonable model for X1. Now, let X2 denote the number of vehicles passing a point on the westbound lane of the same highway in 1 hour. Suppose that X2 has a Poisson distribution with mean λ2 = 3. Of interest is Y = X1 + X2, the total traffic count in both lanes in one hour. What is the P(Y < 5)?