00:01
In this problem, it is given that there is a 23 .4 % probability that a randomly selected resident of the united states, each 25 years or older, is a smoker.
00:10
So we have that the probability that the person is a smoker is equal to 23 .4%, which is equal to 0 .234.
00:19
Again, there is a 21 .7 % probability that a randomly selected resident of the united states, age 25 years or older, is female given that he or she smokes.
00:29
So you can write that the probability that the person is female given that the person is a smoker is equal to 21 .7%, which is equal to 0 .217.
00:41
Now what we need to determine is the probability that a randomly selected resident is female and smokes.
00:47
So we need the probability that the person is a female and is also a smoker.
00:51
So we use the intersection sign and using the formula for conditional probability, this will be equal to p of the person being a female given that the person is a smoker times the probability that the person is a smoker...