mdcat logical reasoning MCQ #389

A researcher claims that all patients with symptom X have disease Y. If a patient has disease Y but no symptom X, what does this indicate about the researcher's claim?

mdcat logical reasoning MCQ #389

  1. Question 1

    Q1. A researcher claims that all patients with symptom X have disease Y. If a patient has disease Y but no symptom X, what does this indicate about the researcher's claim?

    • A) The claim is invalid because the presence of Y without X contradicts it.
    • B) The claim is strengthened as Y can exist without X.
    • C) The claim remains unaffected since Y's presence isn't linked to X.
    • D) The claim is automatically confirmed by this observation.

    Answer: The claim is invalid because the presence of Y without X contradicts it.

    Explanation: A. The claim requires X to always imply Y. Presence of Y without X doesn't disprove it, but presence of X without Y would. B fails because Y without X doesn't support the claim.