Suppose a test for a disease is 85% accurate for those who have the disease (tru

Question

Suppose a test for a disease is 85% accurate for those who have the disease (true positives) and 85% accurate for those who do not have the disease (true negatives). Within a sample of 4000 patients, the incidence rate of the disease is the national average. Complete parts (a) through (c) below. Disease No Disease Total Test Positive 5151 396396 447447 Test Negative 99 35443544 35533553 Total 6060 39403940 4000 a. Use the entries in the table to determine the overall incident rate of the disease. The incident rate is nothing%. (Type an integer or decimal rounded to the nearest tenth as needed.) b. Of those with the disease, what percentage test positive? nothing% (Type an integer or decimal rounded to the nearest tenth as needed.) c. Of those who test positive, what percentage have the disease? nothing% (Type an integer or decimal rounded to the nearest tenth as needed.) Compare this result to the one in part (b) and explain why they are different. In part (b), the comparison is to those who have the disease, those who test positive, and here the comparison is to all those who test positive. all those who have the disease. d. Suppose a patient tests positive for the disease. As a doctor using this table, how would you describe the patient's chance of actually having the disease? Compare this figure to the overall incidence rate of the disease. Choose the correct answer below. A. The chance of having the disease decreases to nothing% given that the test was positive, compared to the nothing% incidence rate without the test. B. The chance of having the disease increases to nothing% given that the test was positive, compared to the nothing% incidence rate without the test.

Explanation / Answer

Given table is

a. The incident rate is

60/4000= 1.5%

b. Of those with the disease, the percentage test positive is

Out of 60 patients with the dease, the percentage test positive 51 is

51/60 = 85%

c. Of those test positive is 447 , the percentage have the disease

51/447 = 11.40%

In part (b), the comparison is to test positive those who have the disease, those who test positive, and here the comparison is to disease all those who test positive. all those who have the disease.

d. The chance of having the disease increases to nothing 11.4 % given that the test was positive, compared to the nothing 1.5 % incidence rate without the test.

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.