Customers arrive at a grocery store at an average of 2.1 per minute. Assume that the number of arrivals in a minute follows the
Poisson distribution. Provide answers to the following to 3 decimal places. What is the probability that exactly two customers arrive in a minute? Find the probability that more than three customers arrive in a two-minute period. What is the probability that at least seven customers arrive in three minutes, given that exactly two arrive in the first minute?
We know that customers arrive at a grocery store at an average of 2.1 per minute. We use the Poisson distribution:
a) In this case:
Therefore, the probability is P(2)=0.270.
b) In this case:
Therefore, the probability is P(X>3)=0.605.
c) We know that two customers came in in the first minute. That is why we calculate the probability of at least 5 customers entering the other 2 minutes.