Question

an athlete suspected of using steroids is given two tests that operate independently of each other. test a has probability 0.9 of being positive if steroids have been used. test b has probability 0.8 of being positive if steroids have been used. what is the probability that neither test is positive if steroids have been used? (a) 0.72 (c) 0.02 (e) 0.08 (b) 0.38 (d) 0.28

Answer 1

The probability that neither test is positive if steroids have been used is; 0.02

How to find the conditional probability?

We are told that;

Probability of test A being positive if steroids have been used is; P(A is positive) = 0.9

Probability of test B being positive if steroids have been used is; P(B is positive) = 0.8

Thus;

P(Both A & B are positive if steroids have been used) = 0.9 * 0.8 = 0.72

P(A is positive and B is not positive if steroids have been used ) = 0.9 * (1 - 0.8) = 0.18

P(A is not positive and B is positive if steroids have been used ) =  (1 - 0.9)  * 0.8 = 0.08

P(Neither A nor B are positive if steroids have been used) = 0.1 * 0.2 = 0.02

Read more about Conditional probability at; https://brainly.com/question/23382435

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