00:01
We are sampling from a small finite population without replacement.
00:05
So can't use a binomial because each choice is not independent.
00:09
We instead use the hyper geometric distribution.
00:16
So here we have 56 numbers, so i'm just going to put n equals 56, and we are picking six of them.
00:27
And we want to know how many of the numbers that we pick are on the winning tickets.
00:32
So there are six winning numbers.
00:34
There are 50 non -winning numbers.
00:36
What's the probability? if we pick six numbers at random, we pick two winnings.
00:43
So the key to a hypergeometric distribution is to have this formula, where you have all the ways to pick tickets in general, so all ways to choose on the denominator.
00:57
And each of these is equally likely to happen because we're picking these six numbers totally at random.
01:01
So one over, however many ways there are to choose them.
01:05
On the numerator, we have the number of ways with two winning numbers and four not winning...