00:01
This question pertains to non -homogeneous poisson processes.
00:07
And normally a poisson process, for a normal poisson process, has a constant rate of arrival for all time.
00:14
But for a non -homogeneous poisson process, the rate of arrival can change with time.
00:19
So in this question, we have a repair facility that's open eight hours each day.
00:24
And the rate of arrivals is dependent on how much of the time of the day has elapsed.
00:30
So for the first hour, we can see that the arrival rate is t.
00:36
And between hours 1 and 7, the arrival rate is 1.
00:40
Between hours 7 and 8, the arrival rate is 8 minus t.
00:46
Now, in part a, we were asked what the probability is that no customers arrive in both the first and last hours of the day, and that four customers arrive in the middle 6 hours.
00:57
So the first thing we can do is find the mean or the expected number of arrivals for each of these periods.
01:07
So let's call the first one mu sub 0 to 1.
01:15
And this is equal to the integral of the arrival rate with respect to time from 0 to 1.
01:30
So this is equal to the integral of t from 0 to 1 which is equal to half.
01:46
So i'll repeat that for the time period from 1 to 7...