00:02
Hello, so we're going to start off by defining some parameters.
00:04
Okay, so we're going to say that a is going to be, let's say, person, less than 25 years old, okay? so a prime is going to be person, greater than or equal to 25 years old.
00:29
Okay, that's going to be a prime, right? and i'm going to say b is going to be pressing that makes a major purchase.
00:44
So let's say there's going to be mixed major purchase.
00:58
All right.
01:00
So we've been giving the following information in the case.
01:03
So we've been given the probability of b, giving a to be 1%, or we can see 0 .01.
01:15
Given the probability of b giving a prime as given in a question as 5 % or you can say 0 .05 right we also have probability of a to be a quarter one fourth yeah into 0 .25 okay so we're going to be finding the probability of a prime and given b and that's going to the probability of a prime and b so that's the definition of that so uh this is also equal to probability of b minus probability a and b over the probability of b okay so all these are just you know something can just look up in the expansions okay so what i'm going to say is i'm going to say this is equation 1.
02:45
Now remember that we have p probability of b given a to 0 .01 right? and this probability of b given a is the same as probability of a and b at the probability of a that's equal to 0 .01 and the probability of a is 0 .25 so you can substitute that.
03:25
So probability of of a, so probability of a and b, probability of a is 0 .25 equals 0 .01.
03:47
So probability of a and b, probability of a and b is going to be got to 0 .25 times 0 .201.
04:03
That's going to be 0 .0025...