Among 143 subjects with positive test results, there are 24 false positive results; among 157 negative results, there are 3 false negative results.

a. How many subjects are included in the study?

b. How many of the subjects had a true negative result?

c. What is the probability that a randomly selected subject had a true negative result?

d. If one of the test subjects is randomly selected, find the probability that the subject did not use marijuana. Do you think that the result reflects the general population rate of subjects who do not use marijuana?

Question

Mathematics

Jazmin Nicholson

11 July, 15:34

Among 143 subjects with positive test results, there are 24 false positive results; among 157 negative results, there are 3 false negative results.

a. How many subjects are included in the study?

b. How many of the subjects had a true negative result?

c. What is the probability that a randomly selected subject had a true negative result?

d. If one of the test subjects is randomly selected, find the probability that the subject did not use marijuana. Do you think that the result reflects the general population rate of subjects who do not use marijuana?

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Answers (1)

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Ana Wang · Answer 1

(a). Total subjects = positive test result + negative test result

Total=143+157 = 300

(b). True negative test result is: 157 - 3=154

(c). P (true negative result) = 154/157

(d). P (not use marijuana) = 143/300. Yes its the result for positive test result.