Question

Nathan had an infection, and his doctor wanted him to take penicillin. Because Nathan’s father and paternal grandfather were allergic to penicillin, Nathan has a 75% chance of having the same allergy. The doctor performed a skin test to see whether Nathan would react to it. The test is 98% accurate. What is the probability that Nathan is not allergic to penicillin and the test predicts it?

0.005
0.015
0.245
0.735

Answer 1

0.245 because of him having the 75% chance of getting it and the test only being 98%

Answer 2

Option 3 is correct.

Explanation:

Given that Nathan had an infection, and his doctor wanted him to take penicillin. Because Nathan’s father and paternal grandfather were allergic to penicillin, Nathan has a 75% chance of having the same allergy. The doctor performed a skin test to see whether Nathan would react to it. The test is 98% accurate.

we have to find the probability that Nathan is not allergic to penicillin and the test predicts it.

As, Nathan has a 75% chance of having the same allergy.

Hence, (100-75)%=25% chance of not having the same allergy.

Also the test predicts given

∴ Probability that Nathan is not allergic to penicillin and the test predicts it is =
`25\%* 98\%`

=
`0.25* 0.98=0.245`

Hence, Option 3 is correct.