00:01
So we're given the following contingency table and we want to find the probabilities, these conditional probabilities.
00:07
So this means we want to know the probability that it was returned given there was money in the wallet.
00:12
Probability it was good return given there was no money.
00:16
Probability it was not returned given money.
00:19
And probability it was not returned given no money.
00:22
So let's start with this first one.
00:25
We want to know the probability it was returned given money.
00:28
So that means we need to look at how many of the wallets had money.
00:32
That's the only numbers we want to look at.
00:34
So we look at there was 300 with money.
00:37
How many of those were returned? 174.
00:41
We'll get our calculator in a few minutes.
00:44
So now let's look at the one probability of not returned given money.
00:48
So we're looking at those same 300 people, wallets that had money.
00:53
How many were not returned? 126...