Use the following results from a test for marijuana use, which is provided by a
ID: 3173568 • Letter: U
Question
Use the following results from a test for marijuana use, which is provided by a certain drug testing company. Among 143 subjects with positive test results, there are 22 false positive results. Among 155 negative results, there are 3 false negative results. Complete parts (a) through (c). How many subjects were included in the study? The total number of subjects in the study was How many subjects did not use marijuana? A total of subjects did not use marijuana. 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 / Answer
The required table will be:
Hence,
a) Number of subjects included in the study = 298
b) Number of subjects did not use marijuana = 174
c) P(Did not use marijuana) = 174/ 298 = 0.584
Use Marijuana Did not use Marijuana Total Test Result Positve 143 - 22 = 121 22 143 Test Result Negative 3 155 - 3 = 152 155 Total 121 + 3 = 124 22 + 152 = 174 143 + 155 = 298