whichscore wrote:
In tests for pironoma, a serious disease, a false positive result indicates that people have pironoma when, in fact, they do not; a false negative result indicates that people do not have pironoma when, in fact, they do. To detect pironoma most accurately, physicians should use the laboratory test that has the lowest proportion of false positive results.
Which of the following, if true, gives the most support to the recommendation above?
(A) The accepted treatment for pironoma does not have damaging side effects.
(B) The laboratory test that has the lowest proportion of false positive results causes the same
minor side effects as do the other laboratory tests used to detect pironoma.
(C) In treating pironoma patients, it is essential to begin treatment as early as possible, since
even a week of delay can result in loss of life.
(D) The proportion of inconclusive test results is equal for all laboratory tests used to detect
pironoma.
(E) All laboratory tests to detect pironoma have the same proportion of false negative results
In all CR questions one should always first understand the conclusion properly , and then focus on how the conclusion can be strengthened / weakened etc.
In strengthen questions we have to find a fact/premise that would reinforce the conclusion in hand.
To do this always prethink an answer that would do one of the above before moving on to the actual answer choices.
Lets take a look at this question
The conclusion here states that "To detect pironoma most accurately, physicians should use the laboratory test that has the lowest proportion of false positive results."
That means physicians are looking for tests that have the tests that detect that one has Pironoma but in actual one does not have it.
Just think for a second why would physicians use this test - maybe because lot of laboratory tests do not detect Pironoma but in actual people have it.
Keeping this in mind we look a the answer choices :
(A) The accepted treatment for pironoma does not have damaging side effects.
- Looks tempting , but focus more closely and you will see that it talks about treatment and not on the conclusion hence ruled out.
(B) The laboratory test that has the lowest proportion of false positive results causes the same
minor side effects as do the other laboratory tests used to detect pironoma.
- again irrelevant
(C) In treating pironoma patients, it is essential to begin treatment as early as possible, since
even a week of delay can result in loss of life.
- irrelevant - talks about treatment rather than detection
(D) The proportion of inconclusive test results is equal for all laboratory tests used to detect
pironoma.
- weakens the conclusion
(E) All laboratory tests to detect pironoma have the same proportion of false negative results
- This about this more carefully , if say all laboratory tests have the same proportion of false negative tests , then why would physicians use use any particular one of them.
On the other hand , one test that has the lowest proportion of false positive test is more useful in determining the disease.
Hope this explanation helps !!!!
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