00:01
Hey there, welcome to numerate.
00:03
We are looking at the probability that a person has hiv and tests positive, knowing that we have a test positive, that they had hiv was 0 .97.
00:17
Conditional probability would test negative, given that they did not have hiv was 0 .926, and the probability of usa having hiv is 0 .906.
00:30
So what we basically have to set up here is our positive predictive value, ppv.
00:41
It's because we have our ppv, which we can depict this in black here, will equal.
00:53
Ppv will equal the conditional probability here.
00:57
So what we basically are given is the 0 .97 multiplied by the probability that a person in the usa has hiv, so which is 0 .0026, and then this is going to be divided by what we have here.
01:29
So we're going to take this probability here and then we're going to add it to one minus our 0 .926 because 0 .926 represents that they did not have have hiv 1 minus 0 .926 multiplied by 1 minus to 0 .0026...