00:01
Hi guys, in this problem, let x denote a random variable that refers to the number of order placed in a week and a city of 800 ,000 people.
00:14
Okay, so x is a possible random variable with lambda.
00:20
Lambda equals 0 .25 times 8, which is 2.
00:28
Okay, so the probability distribution function of the number.
00:32
The possible distribution is given by probability of x equals x it's b power negative lambda times lambda power x over x factorial okay for x equals 0 1 2 etc so in part a we need to compute the probabilities that a technician is required after a one week period so here we we need to find the probability of x where x is more than or equal three.
01:08
Okay, so it's one minus probability of x where x is less than three.
01:15
So it's one minus the probability of x where x equals zero, minus the probability of x equals one, minus the probability of x equals two.
01:31
Okay, so um, this equals to 1 minus e.
01:39
0 .2 times 2 power 0 over 0 factorial.
01:44
Minus e power negative 2 times 2 power 1 over 1 factorial.
01:50
Minus e .0...