rahulbiitk wrote:
AjiteshArun sir, I have the same doubt as Karn. Could you please help if possible?
Hi
rahulbiitk,
Let's take a quick look at the statement we need to strengthen:
GMBA85 wrote:
Clearly, using this test, doctors can largely avoid unnecessary removals of the appendix without, however, performing any fewer necessary ones than before, since __________.
There are two things we need to take care of here:
1. Largely avoid unnecessary removals
and
2. Not perform fewer necessary removals (we can ignore "than before" for the sake of convenience)
This is option C:
GMBA85 wrote:
all of the patients who are diagnosed with this test as having appendicitis do, in fact, have appendicitis
This option tells us that {every case that is identified} is {correctly identified}, but it does not tell us that {every case} is identified. For example, if 100 (out of 100,000) people actually have appendicitis, and this test identifies \(n\) cases, option C tells us that all \(n\) people do, in fact, have appendicitis. But it doesn't tell us that \(n=100\) (or, more accurately, it doesn't tell us that all those 100 people are within the set of people diagnosed with this test as having appendicitis). The test may be "catching" only 98 out of every 100 cases. The remaining people need surgery, but because the test doesn't catch all the cases, they won't get it.
In other words, when this test does identify appendicitis, it is correct, but we don't know whether it catches all cases of appendicitis. This means that there may be people with appendicitis who need surgery but don't get it, which means that, if doctors use this test, they may end up performing fewer necessary removals of the appendix.