Question

*******Helpppppp!!!*******
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

I'm on plato btw

Answer 2

Like I have no clue how to do any of this

Answer 3

I know its not C

Answer 4

Why?

Answer 5

HinT: The chance Nathan has not got the allergy = 100 - 75 = 25%

Answer 6

I got it wrong last time i took it thats how I know I do not understand this lol

Answer 7

Welsh beat me to it, there is a chance Nathan has not got the allergy is 25%, so you just simply multiply that by 98%

Answer 8

0.256?

Answer 9

I guess that's how they want it

Answer 10

0.25 x 0.98 ?

Answer 11

Oh no I divided well I got the same thing ?

Answer 12

I got 0.25510204

Answer 13

It might be C ?

Answer 14

No, you have to multiply since that will give you the probability for Nathan not having the allergy and being allergic to the penicillin

Answer 15

Yes it is C

Answer 16

0.25*0.98 = .245 = 24.5%

Answer 17

Yeah it's a bit confusing

Answer 18

I did I got that , but I got C it was right thanks for the help

Answer 19

Yw

Answer 20

can you help on another one ?

Answer 21

Can you open a new question?

Answer 22

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?
0.1698

0.2217

0.5532

0.7660

Answer 23

I got 0.36 but its not one of my answer choices
@Astrophysics

Answer 24

@baru

Answer 25

sorry, i dont know :(

Answer 26

ok thanks anyway

Answer 27

Tell me your reasoning, all you did was multiply .45*0.80

Answer 28

thats what we did last time so i thought its the same for all of them ? Like on my class I have short lessions so its hard for me to understand what they want me to learn

Answer 29

We did not do that last time, but this seems to require the conditional probability formula https://www.mathsisfun.com/data/probability-events-conditional.html

Answer 30

Okay so how do I do that when I have % ?

Answer 31

Did you read the link? And note for 45% = 0.45

Answer 32

yes I was going through it, but I took 0.45 and 0.80 and divided them and got 0.5625