00:01
In this question, we are going to use the exponential distribution, which is defined as the probability distribution that describes the time between events which occur continuously and independently at an average time.
00:15
The probability density function for this distribution is f of x equal lambda e power negative lambda x or 0.
00:29
For lambda e power negative x, lambda x, its range from x bigger than or equal 0, and 0 will be 0 elsewhere.
00:47
Let capital x, let x has exponential distribution with parameter lambda.
00:55
Then ex will equal to 1 over lambda and varx will equal to 1 over lambda square.
01:03
We have one call every two minutes, so we can say that average time for one call will equal to two minutes.
01:13
The time between calls is exponential distributed.
01:17
So we can say that let x be time between two calls.
01:35
X also has exponential distribution with average two.
01:43
X has also exponential distribution with average time 2 and we need to find the parameter lambda so we can get it as follows 2 equal x equal 1 over lambda from this we can say that lambda would equal to half, 1 over 2.
02:17
So, x approximately be exponential half.
02:30
Now we need to find the average time for 5 calls.
02:35
We need average time for 5 calls.
02:48
We know that for 1 call, we know that for 1 call, we need to.
02:50
2 minute.
02:52
When we finish it for a second, we also need on average 2 minutes.
02:57
So for 2 calls, we need time 2 by 2 equal 4 minutes.
03:18
Now for 5 calls we need 5 by 2, 2, 2 equal to 2 2 2 2 2 2 2 2 2 2...