00:02
For these questions that hiv test told us that 50 % of the people carry with hiv, 0 .50, which means 85 % of people carry without hiv.
00:29
So for those who carry with hiv goes to hospital to do the test, 99 .7 % 0 .99 .97 of the test of the test is correct, which means he or she will be tested positive.
01:02
And then 0 .9 .0 .0 .0 .0 .0 .3.
01:05
0 .03 was incorrect, which means the hospital will tell the patient that she carried without hiv.
01:17
And for the person without hiv went to the hospital to do the test, there is 98 .5 % probability that the test was correct.
01:43
Which means the hospital will tell the patient that he or she didn't carry this hiv, but there are still 0 .0 50 % probability that he or she will test incorrect.
02:10
So the question is, what's the probability that the patient test negative is truly frail of hiv? the probability that the patient without hiv given that he or she test negative.
02:41
So here use the conditional formula, we can have probability without and the test negative, divide by test negative.
02:56
For the numerator, the person without hiv and the test negative, which means is a side.
03:11
The person without hiv and tested correctly...