Final answer:
The question falls under the category of probability and statistics in Mathematics, and it is a college-level problem. It involves finding the average time between customer arrivals and assessing probabilities based on given mean rates.
Step-by-step explanation:
The student's question involves calculating the average time between customer arrivals and the average time it takes for a certain number of customers to arrive, which is a topic in probability and statistics. The given information states that customers arrive at a mean rate of 1 per minute; therefore, on average, the time that elapses between two successive arrivals is 1 minute. This contradicts the provided solution that claims an arrival every two minutes. The correct assessment is to use the initial stated rate. For part b, when the store opens, on average, it would take 3 minutes for three customers to arrive, assuming the arrival rate is indeed one customer per minute.
Statistics often include various measures like means and standard deviations to assess the probability of certain events, such as calculating the probability it takes less than one minute or more than five minutes for the next customer to arrive. These types of problems are critical in business operations to improve customer service efficiency.