00:01
When a veterinarian visits a farm where the sheep are in confined condition, she knows that there's about a 5 % probability.
00:06
The sheep will have a certain disease of the digestive tract.
00:10
So i'm going to go ahead and put these percentages in.
00:15
The vet has a test that can accurately detect this disease 94 % of the time.
00:25
The vet makes a decision to treat every sheep that test positive for the disease with a combative drug regimen.
00:34
So if 5 % have the disease, then that means 95 % do not.
00:42
And we have a test that's accurate, 94 % of the time.
00:47
So maybe instead of positive negative, i'm going to change these to accurate and inaccurate.
00:58
So, oops, let's do that in black.
01:01
So accurate and not accurate.
01:09
So the test is accurate 94 % of time, which means it's not accurate 6 % of the time.
01:16
Complete a two -way frequency table to represent the situation assuming a total sheet population of 100 ,000.
01:23
So filling this in, there would be four.
01:27
Sorry, i want to use black ink.
01:29
4 ,700 diseased that are accurately tested.
01:39
There's going to be 8 ,000...