Jason inherited a piece of land from his great-uncle. Owners in the area claim that there is a 45% chance that the land has oil. Jason decides to test the land for oil. He buys a kit that claims to have an 80% accuracy rate of indicating oil in the soil. If the test predicts that there is no oil, what is the probability after the test that the land has oil?

I think the numerator is 0.36 and the denominator might be 0.11 but I'm really confused about what the denominator B represents. Can anybody help?

Question

Jason inherited a piece of land from his great-uncle. Owners in the area claim that there is a 45% chance that the land has oil. Jason decides to test the land for oil. He buys a kit that claims to have an 80% accuracy rate of indicating oil in the soil. If the test predicts that there is no oil, what is the probability after the test that the land has oil?

I think the numerator is 0.36 and the denominator might be 0.11 but I'm really confused about what the denominator B represents. Can anybody help?

anonymous · Answer

It seems like not a lot of you folks are good at Geometry Conditional Probability equations... it's okay I'll try and find the answer somehow.