Diagnostic tests of medical conditions can have several types of results. The test result can be positive or negative, whether or not a patient has the condition. A positive test (+) indicates that the patient has the condition. A negative test () indicates that 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 of200 patients,some of whom have a medical condition and some of whom do not. Results of a new diagnostic test for a condition are shown.

Condition PresentCondition AbsentRow Total

Test Result + 109 21 130

Test Result 21 49 70

Column Total 133 67 200

Assume the sample is representative of the entire population. For a person selected at random, compute the following probabilities. (Enter your answers as fractions.)

(a)P(+ | condition present); this is known as thesensitivityof a test.

(b)P(| condition present); this is known as thefalse-negative rate.

(c)P(| condition absent); this is known as thespecificityof a test.

(d)P(+ | condition absent); this is known as thefalse-positive rate.

(e)P(condition presentand+); this is thepredictive valueof the test.

(f)P(condition presentand).