In: Statistics and Probability
Customers enter the camera department of a store with an average of 14 minutes between customers.
The department is staffed by one employee, who can handle an average of 13 customers per hour.
Assume this is a simple Poisson arrival, exponentially distributed service time situation.
Find the following information to help the manager decide if a second employee should be added:
The average number of customers waiting. Please keep 4 decimals.
The average time a customer waits (in minutes). Please keep 4 decimals.
The average time a customer is in the department (in minutes). Please keep 4 decimals.
Customers enter the camera department of a store with an average of 14 minutes between customers.
So, the arrival rate = = 14 per minutes = 60/14 = 30/7 per hour.
The department is staffed by one employee, who can handle an average of 13 customers per hour.
So that the service rate = = 13 per hours = 13/60 per minute.
there are only one service channel
Let
Here we assume that this is a simple Poisson arrival, exponentially distributed service time situation.
So we can use M/M/1 model to find the answer of the following questions.
The average number of customers waiting. Please keep 4 decimals.
average number of customers waiting = Expected average queue length E(m) = Lq
average number of customers waiting = 0.1621 persons.
The average time a customer waits (in minutes). Please keep 4 decimals.
Wait in the queue = Wq = Lq/ = 0.1621*14 = 2.27 minutes.
Wait in the system = W = Wq + 1/µ = 2.27 + 1/(13/60) = 2.27 + (60/13) = 6.88 minutes.