What type of service times do the servers at checkout exhibit?

The correct choice indicates that the service times at checkout exhibit an exponential distribution. This is often the case in queuing theory and operations management, particularly in systems like checkout lines, where service times can vary widely and tend to be unpredictable.

Exponential distributions are characterized by the memoryless property, which means that the future service time does not depend on how much time has already elapsed. This makes it a good model for many real-world service processes, including those in retail, where customer service times can be influenced by a variety of factors such as customer decisions, payment methods, and even unforeseen interruptions.

In contrast, a deterministic service time would imply that each checkout process takes exactly the same amount of time, which is rarely the case in practice. Uniform service times would suggest that every service time is equally likely within a specified range, which does not reflect the variability typically observed at checkout. Normal distributions would indicate that most service times cluster around a mean with fewer instances of very short or long service times, which often does not accurately represent the unpredictable nature of checkout services either.

Hence, the characterization of checkout service times as exponential is appropriate due to their inherent variability and unpredictability.