Kevin’s family has a history of diabetes. The probability that Kevin would inherit this disease is 0.75. Kevin decides to take a test to check if he has the disease. The accuracy of this test is 0.85.

We now know that the test predicted that Kevin does not have the disease. Using this information, calculate the probability that Kevin does not have diabetes after the test was taken.
0.0925
0.3565
0.4827
0.6538
0.8765

Question

Kevin’s family has a history of diabetes. The probability that Kevin would inherit this disease is 0.75. Kevin decides to take a test to check if he has the disease. The accuracy of this test is 0.85.

We now know that the test predicted that Kevin does not have the disease. Using this information, calculate the probability that Kevin does not have diabetes after the test was taken.
0.0925
0.3565
0.4827
0.6538
0.8765

anonymous · Answer

Help please? :/ Anyone?

kc_kennylau · Answer

0.85 means that the test is correct at an 85% chance.
Now the test says that Kevin does not have the disease, which means that he has an 85% chance of not having the disease and 15% chance having the disease. Therefore the answer is 15%, which is not on the list of options.

@perl  did i do anything wrong?

perl · Answer

what do you have so far

perl · Answer

we are given
P( disease ) = .75
P( test positive | disease ) = .85
we want to find 
P ( not have disease | test negative )

kc_kennylau · Answer

Wait, when are we given P(test positive|disease) = .85?

kc_kennylau · Answer

I thought we're given that P(test says yes|disease) + P(test says no|no disease) = .85

perl · Answer

im having really bad lag

perl · Answer

the accuracy of the test is .85  
This means that out of 100 people known to have the disease, 85 will test positive.
We can write this in shorthand as 
 P ( + | disease ) = .85  , where + means test positive

anonymous · Answer

Thank you all, im sry computer froze