Critical Reasoning

Which of the following most logically completes the passage?
Appendicitis (inflammation of the appendix) is potentially fatal; consequently, patients with symptoms strongly suggesting appendicitis almost have their appendix removed. The appropriate surgery is low-risk but performed unnecessarily in about 20 percent of all cases. A newly developed internal scan for appendicitis is highly accurate, producing two misdiagnoses for every 98 correct diagnoses. Clearly, using this test, doctors can largely avoid unnecessary removals of the appendix without, however, performing any fewer necessary ones than before, since .

A. the patients who are correctly diagnosed with this test as not having appendicitis invariably have medical conditions that are much less serious than appendicitis


B. the misdiagnoses produced by this test are always instances of attributing appendicitis to someone who does not, in fact, have it

C. all of the patients who are diagnosed with this test as having appendicitis do, in fact,

have appendicitis

D. every patient who is diagnosed with this test as having appendicitis has more than one of the symptoms generally associated with appendicitis

E. the only patients who are misdiagnosed using this test are patients who lack one or more of the symptoms that are generally associated with appendicitis

Ans: [spoiler]B ( I marked E)[/spoiler]

Is it c?

sanjeev.prakash wrote:Which of the following most logically completes the passage?
Appendicitis (inflammation of the appendix) is potentially fatal; consequently, patients with symptoms strongly suggesting appendicitis almost have their appendix removed. The appropriate surgery is low-risk but performed unnecessarily in about 20 percent of all cases. A newly developed internal scan for appendicitis is highly accurate, producing two misdiagnoses for every 98 correct diagnoses. Clearly, using this test, doctors can largely avoid unnecessary removals of the appendix without, however, performing any fewer necessary ones than before, since .

A. the patients who are correctly diagnosed with this test as not having appendicitis invariably have medical conditions that are much less serious than appendicitis


B. the misdiagnoses produced by this test are always instances of attributing appendicitis to someone who does not, in fact, have it

C. all of the patients who are diagnosed with this test as having appendicitis do, in fact,

have appendicitis

D. every patient who is diagnosed with this test as having appendicitis has more than one of the symptoms generally associated with appendicitis

E. the only patients who are misdiagnosed using this test are patients who lack one or more of the symptoms that are generally associated with appendicitis

Ans: [spoiler]B ( I marked E)[/spoiler]

it should B
Passage says... with new test they performer less than necessary....that means someone who has it is getting misdiagonised

Yes answer is B.

But i didn't get ur explanation. B says misdiagnosis is attributed to someone who doesn't has it and ur explanation is just opposite.

sanjeev.prakash wrote:Yes answer is B.

But i didn't get ur explanation. B says misdiagnosis is attributed to someone who doesn't has it and ur explanation is just opposite.

If am reading the following correctly it says..see bold part
he misdiagnoses produced by this test are always instances of attributing appendicitis to someone who does not, in fact, have it

I'm still not able to understand why the answer is b?

I agree that answer choice C is correct. B seems to offer the opposite of the conclusion. In other words if we change the last part of the passage to the opposite, answer choice will fit.

If anybody 100% sure the answer is B, please supply detailed explanation

The answer here is clearly B because there could be two ways of misdiagnosis.

1. Diagnosing a patient as having Appendicitis when "in fact" they don't have it.

2. Diagnosing a patient that they don't have Appendicitis when "in fact" they do have it.

Both are wrong but 2nd one is fatal because "like the recent" swine flu epidemic patients die of the disease thinking that they don't have it because of the diagnosis.

Now, the question says that surgeries are being performed on 20% more cases "unnecessarily". This means that the Case 1 above is rampant. This is not as fatal as Case 2 above. If you are replacing the current method of diagnosis with a new method, you need to be sure that Case 2 above doesn't occur but Case 1 can. Why? Because Case 1 is already occurring 20% of the times. The new method, if it reduces Case 1 and does not "create" Case 2 it should be acceptable.

Among answer choices,

B says, "the misdiagnoses produced by this test are always instances of attributing appendicitis to someone who does not have it ". Which is Case 1 above. This is an acceptable answer.

Continuing my previous post ...

So, what's wrong with C? C here is irrelevant. Let's assume that C is right but then what about the patients who are wrongly diagnosed? The 2% wrong misdiagnosis? Since, 98% of the times it's accurate, there is a 2% chances of wrong diagnosis.

C says,
"all of the patients who are diagnosed with this test as having appendicitis do, in fact, have appendicitis". I agree that this statement can be true but what about those patients who the test says that they don't have the disease but in reality they do have? Case 2 above? Option C does not cover that possibility. If this option is indeed true, as I said before, like swine flu, patients will die thinking that they dont have the disease and those who are diagnosed will get cured because of statement C. The old test, the test "before replacement" did not have this problem.