00:01
We have these probabilities for blood pressure, high blood pressure, and diabetes shown in this table.
00:09
And we are asked for the probabilities of certain events.
00:12
Now one thing we can note is that these probabilities add up to 1.
00:15
So this is a proper probability distribution.
00:19
So these are an exhaustive set of events, which means that everybody has to fall in one of these categories.
00:25
There are no other categories.
00:29
For a, we're asked for the probability that a man has both conditions, so that is diabetes and high blood pressure.
00:40
So that is this condition here, or that corresponds to this cell.
00:46
So that probability is 0 .11.
01:09
For b, we're asked for the probability that a man has high blood pressure.
01:15
You can have high blood pressure by being in either of these categories.
01:18
You can have diabetes or not have diabetes.
01:23
So the probability of having high blood pressure is simply the sum of these two probabilities, which is 0 .27.
01:36
What is the probability that a man with high blood pressure has high diabetes? now if we're talking about a man with high blood pressure, we are only dealing with this column of the table.
01:50
And so the total here is 0 .27.
01:54
So what is the probability that we have high diabetes? it's 0 .11 out of 0 .27, and that's 0 .407 approximately.
02:13
Now i'm not sure if you're asked to write these down like mathematically or not, but this would be the probability of high diabetes given high blood pressure.
02:41
And for d, what is the probability that a man has high blood pressure if it is known that he has high diabetes? so it is known that the person has high diabetes, so we're dealing with this row of the table, and we're asked what is the probability, given that he has high diabetes, that he has high blood pressure.
03:05
Now these add up to 0 .32, and so we have 0 .11 divided by 0 .32...