00:01
We are told that 1 in 10 tickets wins a prize.
00:04
What's the probability of winning at least twice if you purchase 9 tickets? so i'm going to put some parameters down, n and p.
00:13
N represents the number of tickets purchased, p represents the probability of each ticket winning.
00:20
Fair enough.
00:21
But i've written them like this because if we have a look at what's going on here, we have 9 independent trials.
00:28
Each ticket isn't going to influence the others.
00:31
Two outcomes, we win or we don't.
00:33
Same probability for each ticket.
00:36
We have a binomial distribution and that's the key to solving this problem.
00:42
You can use anything that involves binomial probability.
00:46
You could do it by hand with the binomial formula, you could use the tables in the back of the textbooks, or you could use technology.
00:52
Your calculator, excel, r.
00:55
I'm going to use excel with the binomdist function.
01:01
This function has four arguments for me to put in.
01:04
They are x, the number of wins, n, number of tickets, p, probability of winning, and whether or not i want the cumulative probability...