Logical reasoning PrepTest 124 · Section 2 · Question 17

Incorrect. The argument assumes that no test that can effectively diagnose autism at that age existed before this test, but it doesn't require that no test intended to diagnose autism at such an early age existed.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Necessary Premise

Stimulus Summary:
A new test can detect autism at 18 months—it identified all 10 autistic children, but 2 who didn't have it. Therefore, this test can help autistic children receive treatment earlier.

Answer Anticipation:
In order for the autistic children to be able to benefit earlier in life from treatment, it must be the case that the new test is widely deployed, but the argument never establishes that it will be. Sure, it seems very successful at diagnosing autism in those with autism, but it also had two false positives. There's no indication that a test that has such false positives can be deployed.

The argument relies on those two false diagnoses not invalidating the test, so we should look for an answer that establishes the test can still be used even if it occasionally causes someone to be diagnosed with autism despite not being autistic.

Answer Explanation:
This answer establishes that the false positives won't prevent the test from serving as the basis for prescribing treatment. If the false positives did mean that the test couldn't reasonably serve as a basis for such treatment decisions, then the argument would fall apart. This answer is thus necessary for the argument to hold.

Key Takeaway:
While a little less clear than the previous question in the section, this stimulus falls into the same category of providing pros and cons of a certain course of action. Here, the shortcoming isn't that the argument fails to look at both pros and cons, but rather that it doesn't establish that the upside outweighs the noted downside.

Incorrect. The argument doesn't require that all children can be tested—just that the testing can be done widely enough to diagnose autistic children. If that can be done without testing all children at that age, then the argument can still hold.

Incorrect. This answer is tempting and in the general vicinity of our anticipation. However, it's not required that the misdiagnosed children aren't adversely affected at all by the treatments—just that the adverse effects on those children aren't to a level that would prevent the test from being used. If those two falsely diagnosed children are just mildly inconvenienced by the treatments in a manner that's quickly overcome, then that might be more than balanced out by the benefit to the ten children who are correctly diagnosed.

Incorrect. Whether or not people believed autism could affect children as early as 18 months has no impact on whether this test will help those children, so this answer is out of scope.