Logical reasoning PrepTest 120 · Section 4 · Question 14

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Errors in Reasoning

Stimulus Summary:
Only evidence - Handwritten note
Usual suspect - Miller
But the handwriting isn't Miller's so she can't be the practical joker

Answer Anticipation:
Franklin concludes that a person definitely wasn't the practical joker. Why? Because the only evidence he has as to the joker's identity is a handwritten note, and it ain't Miller's.

Does this prove that Miller wasn't the practical joker? Nope—it proves that she didn't write the note. That doesn't mean she couldn't have pulled the prank! Franklin fails to consider the possibility that Miller had someone else write the note for her while still pulling off the prank, so let's find an answer bringing that possibility up.

(Note—If you were thinking that Miller could have changed her handwriting, the stimulus states that it is not hers. Not that it isn't her usual handwriting, but that it is not hers. That's definitive enough for us to discount the possibility that she changed up her handwriting.)

Answer Explanation:
This answer highlights the possibility that Franklin ignores. Miller didn't write the note, but she could have been in cahoots (cahoots we say!) with someone else in pulling off the prank.

Key Takeaway:
One way to approach flaw-based questions is to think about the premises outside of the conclusion and figure out what those premises do establish. Then, you can see where the conclusion goes past it. Here, the premises established that Miller didn't write the note, but the conclusion then goes a step further to clear her of guilt over the practical joke.

Incorrect. The stimulus rules out the possibility that Miller wrote the note, so it doesn't matter how close the samples need to look alike. If the argument went into why Franklin believes she didn't write the note, then this answer might be in play. These types of "it fails to establish the exact number/metric" answers are almost always wrong.

Incorrect. Especially since the argument concludes Miller isn't guilty, it doesn't need to provide a reason to suspect her. The argument doesn't need to justify each statement—some can be premises, which are offered as true without support.

Incorrect. The fact remains that only one piece of evidence was found, so the reason that no other clues were tracked down doesn't matter to the argument.

Incorrect. The argument doesn't assume anything about what would have been the case had the handwriting been Miller's since it's about her not being guilty.