AWS Certified Machine Learning – Specialty — Question 10

A Machine Learning Specialist is implementing a full Bayesian network on a dataset that describes public transit in New York City. One of the random variables is discrete, and represents the number of minutes New Yorkers wait for a bus given that the buses cycle every 10 minutes, with a mean of 3 minutes.
Which prior probability distribution should the ML Specialist use for this variable?

Answer options

• A. Poisson distribution
• B. Uniform distribution
• C. Normal distribution
• D. Binomial distribution

Correct answer: A

Explanation

The Poisson distribution is appropriate for modeling the number of events in a fixed interval of time, particularly for rare events, which fits the scenario of waiting times for buses. The Uniform distribution is not suitable as it implies all outcomes are equally likely, while the Normal distribution assumes continuous data, and the Binomial distribution applies to a fixed number of trials with two outcomes, neither of which aligns with this waiting time scenario.