#### Answer

$0.0947$

#### Work Step by Step

We know that $probability=\frac{number \ of \ good \ outcomes}{number\ of\ all\ outcomes}$, therefore $P(Positive | No drugs)=\frac{90}{90+860}=0.0947$

Published by
Pearson

ISBN 10:
0321836960

ISBN 13:
978-0-32183-696-0

$0.0947$

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