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 had a 75% chance of having the same allergy. The doctor performed a skin test to see wether Nathan would react to it the test is 98% accurate if the test predicts that Nathan is not allergic to penicillin, what is the probability after the test that Nathan is not allergic to thecdrug

Answer 1

These were the choices I found on the internet:
0.1135 
0.2450
0.9423 
0.9932

Other sources can confirm that it is not the second choice. So I'd say it's the third one. Multiply the 98% to the 25% chance of having no allergy to get 0.2450. And for the 0.26, 98% times the 2% percent of error add this to the percent of having no allergy - 0.245 / 0.26 = 0.9423 or 94.23%