Final answer:
The negative binomial distribution is used to model the number of trials needed to achieve a certain number of successes.
Step-by-step explanation:
The negative binomial distribution is used in real-life examples when we are interested in the number of trials needed to achieve a certain number of successes. It models the number of trials until a specified number of successes occur. For example, it can be used to determine how many times a basketball player needs to shoot before making three successful shots, or how many times a student needs to flip a coin before getting two heads.