Question

use the following results from a test for marijuana use, which is provided by a certain drug testing company. among 148 subjects with positive test results, there are 29 false - positive results. among 159 negative results, there are 4 false negative results. complete parts (a) through (c). (hint: construct a table.)
a. how many subjects were included in the study?
the total number of subjects in the study was 307.
b. how many subjects did not use marijuana?
a total of 184 subjects did not use marijuana.
c. what is the probability that a randomly selected subject did not use marijuana?
the probability that a randomly selected subject did not use marijuana is
(do not round until the final answer. then round to three decimal places as needed.)

Explanation:

Step1: Recall probability formula

The probability $P(A)$ of an event $A$ is given by $P(A)=\frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}}$.

Step2: Identify values

The number of subjects who did not use marijuana is 184 (from part b), and the total number of subjects in the study is 307 (from part a).

Step3: Calculate probability

$P(\text{did not use marijuana})=\frac{184}{307}\approx 0.600$

Answer:

$0.600$