Question 3. (25 points) A t-shirt manufacturer makes prints on the t-shirts in his workshop. There are two print machines with equivalent properties. T-shirts arrive at the printing workshop and after the print operation they go to the depot.
a) (15 points) The manufacturer collected data on service and interarrival times during the full working day for 5 days and recorded the time a t-shirt spends in the system. He gives you these data exactly as it is. You use the data obtained from a given date – as it is (without using input distributions) to simulate that day and record the average system time for t-shirts. Table below contains the average system time for the real system and for the simulation for each day. Check the validity of the model.
Input Set Real System Simulation Output
No Average system time (seconds) Average system time (seconds)
1 897.208 883.150
2 629.126 630.550
3 735.229 741.420
4 797.263 788.230
5 825.430 814.190
b) (10 points) Now assume that you calculate the real system time as the average of the above observations (776.85 seconds). You built a simulation model using this information. You made 5 replications with your model and obtained 885.20, 685.50, 801.88, 750.98 ve 825.30 minutes as the average system time. If a difference of 10 minutes is important, test the validity of your model.