1. Problem 3.4 MBPF
A hospital emergency room (ER) is currently organized so that all patients register through an initial check-in process. At his or her turn, each patient is seen by a doctor and then exits the process, either with a prescription or with admission to the hospital. Currently 55 people per hour arrive at the ER, 10% of who are admitted to the hospital. On average, 7 people are waiting to be registered and 34 are registered and waiting to see a doctor. The registration process takes, on average, 2 minutes per patient. Among patients who receive prescriptions, average time spent with a doctor is 5 minutes. Among those admitted to the hospital, average time is 30 minutes. On average, how long does a patient spend in the ER? Assume the process to be stable; that is, average inflow rate equals average outflow rate.

2. Directions o) Draw the flow process chart
b) On average how long a patient spend in ER?
c) On average how many patients are in ER?
Hints:
Compute flow time in buffer 1
Compute average activity time of Doctor
Compute the average flow time in this process
Compute average flow time for a simple prescription patient
Compute average flow time for a potential admission patient
Compute number of patients in Doctor activity
Compute the average number of patients in the process.

3. Flow Time
7.6
37.1
7.5
TD= .9(5)+.1(30) = 7.5
54.2
TPA= = 76.7
TP= .1(76.7)+.9(51.7) = 54.2
TSP= = 51.7

4. Inventory
1.8
6.9

5. The Little’s Law 49.7 Recheck
I = 49.7, R = 55. Is our T= 54.2 correct?
RT= I
R = 55/60 = minutes
RT = I  T=I/R = 49.7/ = 54.2