Question

Phone calls arrive at the rate of 15 per hour at the reservation desk for a hotel, according to a poisson distribution. If no calls are currently being processed, and the desk employee leaves the desk for a 10-minute break, what is the probability the phone will ring while he is gone on his break?

Answer 1

if no calls are being processed is just to throw you off as s poisson distribution is a memoryless property

you want to find the prob of zero rings and then take that away from one

http://www.youtube.com/watch?v=Fk02TW6reiA

this video should explain it

Answer 2

i watched that video just now but it did not help at all. Could you write down the solution for me?

Answer 3

so we are dealing with a 10min time frame ....
find the expected value

1/6*15=2.5