00:01
The first problem, it is said that out of 50 people surveyed in a study, 35 smoke, and was there 20 males.
00:08
We need to find the probability that if the person surveyed as a smoker, then he is a male.
00:13
So we need to find the probability of m given s if we consider m to be the event that a person is a male and s to be the event that a person is a smoker.
00:24
So this is the probability that a person is a male given that the person is a smoker.
00:29
So that's the probability we need to find that if the person is a smoker, then what is the probability that he is male? so using the definition of conditional probability, this is equal to p of m intersection s divided by p of s.
00:42
So first of all, consider p of m intersection s.
00:45
This is the number of favorable outcomes divided by the total number of outcomes.
00:49
Now the total number of outcomes will be the total number of people surveyed and that is given to be 50.
00:54
Now, since intersection represents and, so the number of favorable outcomes will be the number of of people who are both male and smokers.
01:02
Now it is said that out of the 50 people surveyed 35 smoke and out of those 20 of them are male.
01:09
So out of the 35 smokers, 20 are males.
01:12
That means 20 people are both smokers and males and so the number of favorable outcomes.
01:17
That is the number of people who are both males and smokers.
01:19
That will be 20.
01:21
Next consider p of s.
01:23
This is the probability of being a smoker...