Note: Sorry if this is considered a uni question, I'm not sure, so you'll have to tell me.
The question
A busy switchboard receives 150 calls an hour on average. Assume that the probability, , of getting k calls in a given minute is:
where the average number of calls per minute.
a) Find the probability of getting exactly 3 calls in a given minute.
b) Find th probability of getting at least 2 calls in a given minute.
I'm not sure how to attempt this. I'm sure I'm missing something obvious, but there's no examples in this text to guide me. Any assistance would be great.
Your answer to a) doesn't match the textbook solution of 0.214
Even by intuition (as bad as it tends to be for probability) it looks much too small.
I'm yet to find a solution myself. :/