Question: Survey: Medical Tests

Diagnostic tests of medical conditions have several results. The test result can be positive or negative, whether or not the patient has the condition. A positive test (+) indicates the patient has the condition. A negative test (-) indicates the patient does not have the condition. Remember, a positive test does not prove the patient has the condition. Additional medical work may be required. Consider a random sample of 200 patients, some of whom have a medical condition and some of whom do not. Results of a new diagnostic test for the condition are shown.

Assume the sample is representative of the entire population. For a person selected at random. Compute the following probabilities:

a. P(+, given condition Present); This is known as the sensitivity of a test.

b. P(-, given condition Present); This is known as the false negative rate.

c. P(-, given condition absent); This is known as the specificity of a test.

d. P(+, given condition absent); This is known as the false-positive rate.

e. P(condition present and +); this is the predictive value of the test.

f. P(condition present and -).