Logical Reasoning · Flaw
PrepTest 152 · Section 2 · Question 18
Phase 1 (your first ~400 questions): read the guidance, then answer. No clock.
Step 1 · Pre-Question Guidance · read this first
- “typically”
- “usually”
- “must be”
- “a cause”
Playground logic
Marcus notices that kids with more stickers usually get better spelling scores, and that field trips usually bring more stickers. His top bun says field trips cause better spelling. That is the Rooster: a match between stickers and scores is treated as if the stickers did the work.
Step 2 · The kid story
The Sticker Detective
Marcus pinned a chart to the classroom wall. "Look," he said. "Kids with lots of stickers on their folders usually get high spelling scores. And field trips usually give us extra stickers, because the bus driver hands them out. So field trips must make us better spellers!" Priya sipped her juice box. "Marcus, the stickers and the scores travel together. That does not mean stickers make anyone spell better." Lulu checked her clipboard. "Ms. Rivera gives stickers for good spelling. Maybe the scores bring the stickers, not the other way." Marcus frowned. "But the line on my chart goes up!" "So does the line for how tall we are," said Priya, "and growing does not teach spelling either." Marcus slowly unpinned his chart. "Detective work is harder than it looks."
Step 3 · Try the model question
Marcus: Kids with more folder stickers typically earn higher spelling scores. Field trips usually raise the number of stickers a kid has. So field trips must help produce high spelling scores.
Which choice best names the weak spot in Marcus's reasoning?
Step 4 · The courtroom tale
The Case of the Umbrella Sales
Mr. Whitfield snapped his suspenders. "Your Honor, the prosecutor says that whenever umbrella sales go up, puddles in the town square go up too. And the parade usually boosts umbrella sales. So, she claims, the parade must cause puddles." The judge raised an eyebrow. Mr. Whitfield went on. "Umbrellas and puddles rise together, yes. Both rise when it rains! Nobody showed that a single umbrella ever poured water on the square." The prosecutor shuffled her papers. "Matching lines are not a push," said the judge. "Case dismissed, and somebody please fetch me an umbrella."
Step 5 · Work the real question
Open PrepTest 152, Section 2, Question 18 in your official copy from LSAC (for example in LawHub) and read it there.
Your answer
How to apply it
Write the top bun in your own words: something is a cause of an effect. Then look at the patty and ask what link it really gives. If the support is only that two things tend to rise together, you have the Rooster. Pick the choice that says a correlation was treated as a cause. Ignore choices that describe a reversal, a chain, or a hidden blocker unless the argument truly makes that exact move.