Customers arrive at a checkout counter in a department store according to a Poisson distribution at an average of nine per hour. If it takes approximately ten minutes to serve each customer, find the mean and variance of the total service time in minutes for customers arriving during a 1-hour period. (Assume that a sufficient number of servers are available so that no customer must wait for service.)
μ= min
σ2 = min
Is it likely that the total service time will exceed 3.5 hours? (Round your answer to three decimal places.)
Since P(service time exceeds 3.5 hours) = , this is
---Select--- a likely an unlikely event.
You may need to use the appropriate appendix table or technology to answer this question.