00:01
We're looking at roulette, and we want to find the expected value of a particular bet.
00:05
So you can bet $2 on red.
00:08
Okay, and if it lands on red, you keep your $2 and you get four.
00:13
If it lands elsewhere, you get nothing, and you lose your $2.
00:16
So how do we find expected value? so expected value is the mean of the probability distribution.
00:25
They're the same thing.
00:26
And to get it, you take each possible outcome, you multiply by its probability.
00:31
And you add these up.
00:34
It's a lot like finding the mean of a frequency table.
00:37
So let's make a probability distribution.
00:39
We need outcomes and we need their probabilities.
00:44
So you could win.
00:46
If you win, you don't have to pay anything out and you gain $4.
00:51
Or you could lose.
00:52
If you lose, your net profit is negative 2.
00:58
You lose $2.
01:00
What's the probabilities of these happening? okay, so we have 1 to 36 and then we have 0 and 0.
01:12
So a roulette table has 18 red, 18 black, and these have the numbers 1 to 36, and then it has 2 that are green, and those are 0...