Probability distribution

Question

The arrival time of an elevator is equally likely at any time range during the next 4 minutes. a. Calculate the expected arrival time. b. What is the probability that an elevator arrives in less than 1 ½ minutes? c. What is the probability that the wait for an elevator is more than 1 ½ minutes?

Answer 1

Hi Shyam S.,

You may best view this graphically. Graph the probability "density" for arrivals vs. t: it is a rectangular block over the 0 - 4 mintute range. Then the intuitions about cumulative arrival probability are just basic mental calculations from the various rectangular sub-blocks of that.

-- Cheers, --Mr. d.