The Center for disease control estimates that 51% of U.S. population suffers fro
ID: 3045251 • Letter: T
Question
The Center for disease control estimates that 51% of U.S. population suffers from coronary artery disease (CAD) on any given year. A study investigated the use of a technique called radionuclide ventriculography as a diagnostic test for detecting CAD in asymptomatic patients. To evaluate the testing technique, the investigators used the test on randomly selected 481 subjects who are known to be suffering from CAD. Of these 481 subjects, 179 test results were negative. The investigators used the test on another group of randomly selected 452 healthy subjects, of whom 80 test results were positive.
a)What is the sensitivity of radionuclide ventriculography in this study?
b)Calculate the probability that an individual has the disease given that he or she tests positive on radionuclide ventriculography.
C)What is the predictive value of a negative test?
d)Suppose that 10,000 subjects randomly selected from the U.S. population test negative for coronary artery disease by the radionuclide ventriculography. How many of these 10,000 subjects are expected to be actually disease free?
Explanation / Answer
following information has been given
(a)Sensitivity: A/(A+C) × 100=100*302/481=62.79
(b)probability that an individual has the disease given that he or she tests positive=302/382=0.79
(c)Negative Predictive Value: D/(D+C) × 100=100*372/551=67.51
(d)P(positive disease person)=302/933=0.323687
P( disease free)=1-P(positive disease person)=1-0.3237=0.6763
required number=0.6763*10000=6763
disease non disease positive 302(A) 80(B) 382 negative 179(C) 372(D) 551 481 452 933