Answer:
Step-by-step explanation:
60 minutes = 1 hour
The statement would be
"Customers arrive at a checkout counter in a department store according to a Poisson distribution at an average of seven per 60 minutes
If it takes approximately ten minutes to serve each customer, then the mean service time for in minutes for customers arriving during a 1-hour period is
10/60 × 7 = 1.67
In Poisson distribution, variance = mean
Therefore,
Variance = 1.67
The probability that the total service time will exceed 2.5 hours is expressed as P(x > 2.5)
Converting 2.5 hours to minutes, it becomes 2.5 × 60 = 150 minutes
From the Poisson distribution calculator,
P(x > 150) = 0
