Why are the arrival of patients at a physician office and the arrival of commercial airplanes
Why are the arrival of patients at a ph ysician 's office and the arrival of commercial airplanes at an airport not Poisson random variables?
The mean nu mber of patients arriving at the emergency room of Uni versity Hospital on Saturday nights between 10:00 and 12:00 is 6.5. Assuming that the patients arrive randoml y and independently, what is the probabilit y that on a given Saturday night, 5 or fewer patients arrive at the emergency room between 10:00 and 12:00?