Logical Reasoning · Flaw
PrepTest 129 · Section 2 · Question 6
Phase 1 (your first ~400 questions): read the guidance, then answer. No clock.
Step 1 · Pre-Question Guidance · read this first
- “tend to”
- “studies show”
- “by promoting”
Playground logic
The coach's patty: soccer players tend to finish homework, and late-night gamers tend not to. His top bun: push kids into soccer and away from late gaming, and grades will climb. That is a Rooster: just because two things are found together does not mean one causes the other.
Step 2 · The kid story
Coach Owen's Homework Plan
Owen's big brother coaches the after-school soccer club. He made a chart. "Look," he said. "Kids on the soccer team tend to finish more homework than most kids. Kids who play video games late tend to finish less. And finishing more homework usually means better grades. So the school can raise grades by getting kids to join soccer and to stop gaming late!" Marcus nodded hard. "Detective Marcus agrees!" Priya sipped her juice box. "Wait. Maybe kids who already finish their homework are the ones whose parents let them join soccer. The soccer might not be doing anything." Lulu wrote: Together does not mean causes. Biscuit chased the soccer ball, which proved nothing.
Step 3 · Try the model question
Kids on the soccer team tend to finish more homework than most kids, and kids who play video games late tend to finish less. Finishing more homework usually means better grades. So the school can raise grades by getting kids to join soccer and discouraging late gaming.
The coach's reasoning is flawed because it
Step 4 · The courtroom tale
The Case of the Lucky Socks
The prosecutor waved a graph. "Your Honor, umpires who wear striped socks tend to make fewer bad calls. Umpires who drink lots of soda tend to make more. So the league can improve its calls by requiring striped socks and banning soda!" Mr. Whitfield stood. "Your Honor, those things travel together. That does not mean socks fix eyesight." "Explain." "Perhaps the most careful umpires also happen to like stripes. Careful people may simply drink less soda too. Being careful could explain both." The judge squinted at the graph. "So you are saying the socks are a passenger, not the driver." "Exactly. Two things riding together does not tell you who is steering."
Step 5 · Work the real question
Open PrepTest 129, Section 2, Question 6 in your official copy from LSAC (for example in LawHub) and read it there.
Your answer
How to apply it
Find where the evidence comes from: a study showing that certain traits tend to show up together. Then read the conclusion: does it recommend changing one trait to produce a change in another? If so, predict the causal leap. Pick the choice that names treating a correlation as causation; cross off choices describing moves the argument never makes.