PT61.S2.Q20 - When people show signs of having

huq1417huq1417 Alum Member
edited June 2018 in Logical Reasoning 8 karma

why C is correct?

my understanding is that "when people show signs of having a heart attack, EKG is used", so the "cases in which no heart attack occurred", they probably not use EKG, so it's out of scope, because the conclusion is about "Interpreting EKG data".

Admin note: edited title
https://7sage.com/lsat_explanations/lsat-61-section-2-question-20/

Comments

  • BinghamtonDaveBinghamtonDave Alum Member ⭐ 🍌🍌
    8716 karma

    When the people are displaying symptoms: lets say chest pain, further testing is provided. Note the first sentence here: the move from symptom to diagnosis. Presumably, someone can have a symptom without a diagnosis: chest pain could be something other than a heart attack. Both the doctor and the machine look to diagnose whether the symptom was a heart attack.

    The flaw in this argument is we are basing a judgement on what is better: doctor or machine on the basis of possibly incomplete information: just the positive diagnosis. Meaning the machine says: "yes thats a heart attack" and gets a higher percentage "correct" than the doctor. This leaves open the odd, but nonetheless flawed possibility that the machine was simply saying "yes, thats a heart attack" to every patient. A true rendering of who/what is better at diagnostics would include both diagnostics of both positive (yes, thats a heart attack) and negative (no, that symptom is not a heart attack) instances.

    So lets look at a situation:
    10 patients, 4 have heart attacks present and 6 do not

    the computer correctly guesses the 4, but incorrectly guesses the 6.
    the doctor correctly guesses 3 of the 4, and correctly guesses the 6.
    This brings the total to:
    Machine: 4 corrects
    Human: 9 corrects

    In the situation described above, how can we say the machine is better? Thats what (C) does for us.

    The key for future questions: ask ourselves, is this the full spectrum of data or is this half??

    David

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