Use the following results from a test for marijuana use, which is provided by a
ID: 3376248 • Letter: U
Question
Use the following results from a test for marijuana use, which is provided by a certain drug testing company. Among 145 subjects with positive test results, there are 20 false positive results; among 159 negative results, there are 5 false negative results. If one of the test subjects is randomly selected, find the probability of a false positive or false negative. (Hint: Construct a table.) What does the result suggest about the test's accuracy? The probability of a false positive or false negative is (Round to three decimal places as needed.)Explanation / Answer
Probability of False positive (Type-1 error) = 20/304 = 0.066
Probability of False negative (Type - 2 error) = 5/304 = 0.016
Test accuracy = 1 - 0.066 - 0.016 = 0.918
Test accuracy>90% which is excellent.
The probability of a false positive of false negative = 0.066 + 0.016 = 0.082
Probability True False Test predicting true 125 20 Test predicting False 5 154